<prompt> Human: My girlfriend and I have been trying to start our own businesses for about a year now. Were at the point where we can live off of the income that she gets from flipping appliances, and I from flipping ohvs. If we were to do that, Id have no clue how to pay income taxes for either of us, or what things are deductible. What should I keep track of and who do I go to with all this information at the end of the year? Does it matter that some ohvs I buy and sell dont have titles?... Also, how do I pay for all of the other taxes besides income? Would it be better if she and I created a single business, or if we created our own?  <response>: I think you would want to have separate businesses, each tracking its own expenses.Schedule C or C-EZ is used to track your revenue and subtract deductible expenses. For your businesses, those expenses include cost of goods you flip. Its only the resulting profit that gets taxed, so keeping good records of deductible expenses is important. See also IRS Publication 535.Schedule SE is used to calculate Social Security and Medicare taxes. It starts with the Schedule C profit. The Schedule SE info gets used by Soc Sec Administration, so your earnings count in your record and might influence your Soc Sec benefit later. This is one reason for filing two separate businesses: each of you gets credit for Soc Sec that way.Form 1040 is the tax form you have to use. The Sched C result goes on line12, the Sched SE result on line 57, and a number equal to half of Sched SE result goes on line 27 as a deduction. Income tax will show up on line 44, but the SE taxes on line 57 get added to that.If you also have other income from W-2 jobs, you can choose to increase withholding by filling out a new W-4 to be sure you dont underwithhold and dont owe a lot at tax time. Or you can use Form 1040-ES booklet worksheets and make four estimated tax payments. Whichever approach you use, at tax time when you file your taxes you learn if you sent in too much or not enough, and get a refund or owe. IRS wants you to have sent in 90 of your tax during the year -- or 100 of previous years tax if smaller. If you simply wait until tax day to send it all in, you could have an underpayment penalty even though you paid in full.There is an area at IRS site with resources for small businessesself-employment. Also there are books about this too. 