Middle to Low Range Budgets

Going cheaper than the above is certainly possible. Airline tickets should be somewhat cheaper off-season, or a great deal or sale could cut their price. Don’t plan on this, though; prices could just as easily go up. Camping would help the most and could cut that USD 1500 accommodation chunk by half. It would do this, however, at an increased cost in city transportation, and greatly increased time spent toting packs around. A cheaper train pass or a bus pass could help squeeze a bit, as could cheaper food and fewer incidentals - buying food at stores and cooking it for yourself can save major dollars. If you like pasta, or rather if you like cooking pasta, you can eat cheaply pretty much everywhere. Traveling as a couple, you can save some money over single travelers, and you will have more privacy while you save.

Unless you want to hitchhike, sleep in train stations, and eat bread three meals a day, I would count on spending an absolute minimum of about USD 3600/4000 (depending on age - see below) for two months. This is a daily total of about USD 35 per day, without transportation. Note that this last budget cannot be cut substantially anywhere.