Last year i went on touring trip with bicycle worth 50 eu which is $54 around 6000 km across 12 countries. My bike load was 50 kg. I had 4 panniers on front and rear and i have to say that cost of bike is not important at all. I prefer to have a bike with less equipment because there is less likely to break and less chance to be stolen.

EDIT:

link: https://i.sstatic.net/05NeQ.jpg

My budget was 260 eu/$281.92 for two months.