16. A method of facilitating online transactions involving seller financing and notifying users of time limited offers in an online marketplace, using at least one computing device, the method comprising: generating and storing trust profiles for buyer users and seller users, using the at least one computing device, the trust profiles configured to allow both the buyer users and the seller users to evaluate trustworthiness of each other prior to entering into online transactions involving seller financing, wherein the trust profiles include reputation data including: reputational factors, including: at least one rating of at least one of the user's prior transactions, from another user; historical data about the user's conformance to terms of the user's prior transactions; and information about a verification level of the user; and a trust score computed based on at least some of the reputational factors, including a number of the user's prior transactions; and receiving descriptions of a plurality of transaction offerings from a plurality of seller users of the online marketplace, using the at least one computing device, wherein the transaction offerings are available for purchase from the seller users over time for at least two payments; generating a user interface presenting a plurality of listings and the trust profiles using the at least one computing device, each of the listings including one of the descriptions of the plurality of transactions offerings, wherein the plurality of listings are associated with transaction offerings across a plurality of different transaction offering categories; presenting at least some of the plurality of listings to buyer users through the user interface, using the at least one computing device; and facilitating, using the at least one computing device and through the user interface, negotiation of binding contracts between the buyer users and the seller users for transfer of the transaction offerings from the seller users to the buyer users, wherein the binding contracts define payment terms, and wherein the payment terms include prices and seller-financing terms including at least two payments made by the buyer users to the seller users over a period of time, comprising: receiving an offer from a first user of the buyer users and the seller users for one of the transaction offerings, the offer including offer details and a time limit generating an offer alert from the offer that includes the offer details, the time limit, and a customized link, which is selectable by a second user of the buyer users and the seller users to view the offer on the online marketplace; formatting the offer alert according to a preferred offer communication method for the second user; transmitting the formatted offer alert to the second user over a wireless communication network, wherein the formatted offer alert upon receipt instantaneously activates an application on a remote computing device to display the formatted offer alert and enable connection via the customized link to the online marketplace over the Internet upon connection of the remote computing device via the customized link, generating for display on the remote computing device to the second user: a listing for the one of the transaction offerings; the offer including the offer details; the trust profile for the first user; and an option to accept the offer; and receiving an acceptance from the second user.
16. A method of facilitating online transactions involving seller financing and notifying users of time limited offers in an online marketplace, using at least one computing device, the method comprising: generating and storing trust profiles for buyer users and seller users, using the at least one computing device, the trust profiles configured to allow both the buyer users and the seller users to evaluate trustworthiness of each other prior to entering into online transactions involving seller financing, wherein the trust profiles include reputation data including: reputational factors, including: at least one rating of at least one of the user's prior transactions, from another user; historical data about the user's conformance to terms of the user's prior transactions; and information about a verification level of the user; and a trust score computed based on at least some of the reputational factors, including a number of the user's prior transactions; and receiving descriptions of a plurality of transaction offerings from a plurality of seller users of the online marketplace, using the at least one computing device, wherein the transaction offerings are available for purchase from the seller users over time for at least two payments; generating a user interface presenting a plurality of listings and the trust profiles using the at least one computing device, each of the listings including one of the descriptions of the plurality of transactions offerings, wherein the plurality of listings are associated with transaction offerings across a plurality of different transaction offering categories; presenting at least some of the plurality of listings to buyer users through the user interface, using the at least one computing device; and facilitating, using the at least one computing device and through the user interface, negotiation of binding contracts between the buyer users and the seller users for transfer of the transaction offerings from the seller users to the buyer users, wherein the binding contracts define payment terms, and wherein the payment terms include prices and seller-financing terms including at least two payments made by the buyer users to the seller users over a period of time, comprising: receiving an offer from a first user of the buyer users and the seller users for one of the transaction offerings, the offer including offer details and a time limit generating an offer alert from the offer that includes the offer details, the time limit, and a customized link, which is selectable by a second user of the buyer users and the seller users to view the offer on the online marketplace; formatting the offer alert according to a preferred offer communication method for the second user; transmitting the formatted offer alert to the second user over a wireless communication network, wherein the formatted offer alert upon receipt instantaneously activates an application on a remote computing device to display the formatted offer alert and enable connection via the customized link to the online marketplace over the Internet upon connection of the remote computing device via the customized link, generating for display on the remote computing device to the second user: a listing for the one of the transaction offerings; the offer including the offer details; the trust profile for the first user; and an option to accept the offer; and receiving an acceptance from the second user. 21. The method of claim 16 , wherein presenting a listing to a buyer user comprises presenting the proposed seller-financing terms, including price, payment amount, payment frequency, and number of payments, and further including an amortization schedule.