Our payment processor - CCBill - has certain rules and restrictions regarding payments from countries that they consider problematic (larger percentage of fraud etc). We're not really happy about those restrictions - we'd prefer to accept payments from almost all countries - but we have to respect them. BUT we did manage to negotiate some new conditions so here is an approximate list of countries and payment possibilities.
90% of world countries
Belarus
Bulgaria
Costa Rica
Ecuador
Estonia
Kazakhstan
Lithuania
Sri Lanka
Argentina
Brazil
Colombia
Indonesia
Malaysia
Peru
Philippines
Romania
Serbia
Ukraine
Czech Republic - home of most of our models
Slovakia - home of some of our models
Russia - global block due to too many hack attempts and thefts
Mostly third-world countries or countries with complicated domestic or financial policy - Azerbaijan, Brunei, Congo, Cuba, Dominican Republic, Ivory Coast, Jordan, Nepal, Kyrgyzstan, Macedonia, Montenegro, Nepal, Pakistan, Sudan, Syria, Vietnam, Zimbabwe and possibly others (the list can be updated from time to time).