Best cheapest, interesting, safe countries??

We are just beginning to plan a year-long trip, probably linking 12 countries to spend a month each in. We are looking for 12 cheap, interesting, safe countries. We usually try to vacation in "value" countries where we can get by nicely for $50/day for the two of us. At that budget we want to stay in pensions, guesthouses and small hotels--no hostels or dorms. We like a quiet sit-down relaxing dinner every night.
These are the places we have already been to that I would call pretty cheap:
Czech Republic
Poland
Hungary
Slovenia
Croatia
Greece
Turkey
Thailand
Korea
Cambodia
How about other countries?? Cheaper countries?? Ideally, we really would like to link 12 easily yet provide a cultural diversity.

Some suggestions:

Tunisia
Slovakia (cheaper than Poland, Czech Rep. or Hungary)
Serbia (though budget accommodation isn't always easy to find)
Mongolia (if you're willing to reconsider the no dorm thing - there are hotels in UB but they're not very good value compared to the guesthouses, and in the countryside you'll mostly have a choice between camping, staying with locals, or soulless tourist ger camps)

I forgot I've been to Slovakia many times. I LOVE the Tatras!!! Thanks for reminding me--it would be worth going again because my husband hasn't been there.

Here's an article on the subjectthat might be helpful.

You shouldn't have much trouble on that budget.

you thought Greece was cheap? hmm...
well I suppose if you can find the right guesthouses, and don't go in high season it would be reasonable.

I would recommend Bulgaria. it appears to have an up and coming economy, things are definitely growing and the tourism infrastucture appears to be improving, but it's still CHEAP. A good dinner, even in some touristy areas can be as cheap as 15 Leva for 2 (that's about 7.5 Euro). cheaper hotels, guesthouses, especially in smaller towns, and outside of the major areas, can be 30 Leva (15 Euro). and it's a beautiful country! so green and lush, and the people are great.

I also recommend Turkey, but it looks like you've been there. it's one of those places that I'll probably visit several times in my lifetime. there's just too much to see, and the hospitality is great.

I don't know about one month in each, but maybe consider spending 2 weeks each in Syria and Jordan; Jordan is a bit more expensive, but Syria is cheap enough to offset it. They are both lovely places, especially if you have any interest in Arab culture. for a different experience, try spending a couple of days in the desert with some Bedouin. There are a few companies in Jordan that offer different adventure activities in the Wadi Rum. The people of both countries are so wonderful - we were invited home for lunch/dinner/tea several times!