How can I buy apps from unsupported countries? What can you do if you are located in a country that still does not support paid apps?  Please include solutions for non-rooted users as well.
Requirements


a google checkout account with valid credit card (this has no country limitations)
pre-paid SIM card from supported country (for me pre-paid Three UK SIM worked just fine)


Steps for purchasing


insert the pre-paid SIM
enter google account that is associated with google checkout (account will be asked because of SIM change)
connect over Wi-Fi
purchase the wished application
just download and install


Questions

What about roaming charges? As a rule pre-paid SIMs do not work in other countries, so the only way to browse the market and download applications is connecting over Wi-Fi.

Why is a SIM required? Market detects Your location by SIM cards home country. By using a SIM from supported country You are effectively faking Your location.

Isn't it required for Google Checkout account or credit card used to be in supported country? It seems that not. For me these were both located in Estonia and everything went without problems.

What if application is using some weird copy protection that locks it to a specific SIM card? Would the app not stop working when real SIM is swapped in? To prevent this kind of copy protection on locking to the incorrect SIM the easiest option is to cancel the download after purchase has been complete. Swap the real SIM in and complete the download. If there is some kind of SIM check, it can be only done after installation has been complete.

Where can I get a pre-paid SIM card? Check eBay :) There is no actual credit required on the SIM, so these should be pretty cheap.

--credit: the poster himself (JaanusSiim)