Excellent write up.

This is a list of Osterie in the Slow Food network divided by regions featuring <35 euro all-in deals: http://www.scattidigusto.it/2014/09/...15-chiocciole/
Sorry only in Italian.

Can't stress enough what Perche uses to say; eating off the tourist paths (and most of times you just really need an extra mile to do it) rewards immensely your palate and wallet.

As a tourist I'd hit undoubtedly only Trattorie and Osterie all over Italy. Slow food is an excellent starting point.