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.
Steps for purchasing
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)
For rooted phones:
There is an app called Market Enabler that allows you to fake which country and carrier you're on when you're browsing the market so that you can easily browse markets from other countries or carriers. using this you should be able to connect to other European markets (I don't know which country you're in but many European markets such as UK do allow paid apps, you don't have to go to the US for them).
I think you'd need to have a credit card that has a billing address in the US (or other supported country).
In Europe apps can be bought by users in Austria, France, Germany, Italy, Netherlands, Spain, the UK, and Switzerland.
Hopefully the number of supported countries will be increased when Google announces its apparently imminent Market improvements. The recent change to the terms and conditions to allow for carrier billing and rumours of Paypal support suggest that there will be new payment options in the near future, potentially for countries where Google Checkout is not currently available.