How deep should it be? Average for all municipalities in country  (NTS-1, NTS2... level) or very detailed? For  example http://www.oecd-ilibrary.org/docserver/download/4209151ec007.pdf?expires=1432161307&id=id&accname=guest&checksum=0D9BDA9A084BA33E0DCC4F363AEEFB01.

For Poland we have precise databases on www.stat.gov.pl or on Ministry of Finance website (You can explore each "paragraph" of revenues or expenses. 

Hi,

Here is another, more recent one from OECD: http://www.oecd.org/ctp/federalism/oecdfiscaldecentralisationdatabase.htm

Plus the Eurostat database:http://ec.europa.eu/eurostat/web/government-finance-statistics/statistics-illustrated

If you need disaggregated data, call me I have some on the Western Balkan countries

Thanks you Jaroslaw and thank you Gabor. Actually these databases are really useful for analyzing state income and expenses. What I need is municipal budgets separately. 

You should look, first, at the IMF Government  Finance Statistics, They are not referred specifically to municipalities,  but to local government, of which municipalities are the biggest component. They have good quality and comparability. Also the OECD has very good data, particularly on revenue. CEPAL is a good source for Latin America. Otherwise you have to refer to national data, which in many countries is very good. I can be more detailed on this.