A few cheap yummy Belgian treats are fries, gaufres (waffles) and crepes (from the French tradition). Both fries and gaufres can be found virtually at every corner and every metro station in a greasy but delicious version.
I have had very good fries at Frit Flagey (Place Flagey-Rue Gray, Ixelles). The man is not exactly friendy, but the portion of fries is abundant and the fries themselves nice and crunchy. Another plus is the huge selection of sauces you can add to your portion of frites!
If you’re more of a sweet person, good light gaufres (and crepes) can be found around Merode metro stop at Sel et Sucre (Avenue des Celtes 4) open till 6pm on Monday and till 10pm from Tuesday to Thursday. They serve the Brussels gaufre, not the Liege one! The gauffre nature is €4 but it’s very big and satisfying I promise! The place is also interesting as it’s the ground floor of a house and everything is made on spot using a domestic kitchen.
Another nice spot for crepes is a small ‘crèperie bretonne’ just on rue du Luxembourg. It’s called Crepes and co. Around lunchtime it is packed, but the crepes are good and not too expensive. You can choose between a good range of savoury and sweet crepes. It was a Breton man who pointed this place out to me, so he knows what he’s talking about!
Naturally, beer is good everywhere in Belgium: if you like it, drink it! My personal favourites are the Chimay Bleue (dark and very strong, 9%), Hoegaarden Blanche (from the white ones, thick but light 4,5%) and Leffe as a general good brand of both blonde and dark beer (personally recommend the Brune, 6,5%). Avoid the Kriek if you don’t like fruit flavoured beers (it’s cherry flavoured! How can anyone think that’s good?!). Cheap beers are the Jupiler, Stella Artois and Palm and although they are better than any Italian beer, I wouldn’t suggest them if you want to have a real taste of Belgian beers. Instead go for any of the Trappist or the Abbey ones. Another well-known and popular beer is Orval, although personally I find it too bitter.