Hi elliejah
Dragging toes causing you to trip is most likely to do with weakness of the ankle muscles that lift the foot (tibialis anterior, extensor digitorum) - but you have probably worked that out yourself. Feeling like you can't get up stairs could involve some of the large muscles in your leg that work against gravity. There could be a large number of causes for this weakness. Why it is intermittent is an important point in diagnosing it. However to have weakness in the foot like that, particularly someone of your age needs to be taken seriously. There are some potentially quite serious conditions that can give you weakness. I am not saying you have a serious condition but I think you should get it properly investigated to get a proper diagnosis. I suggest you should ask to see a neurologist with the aim of ruling out anything serious and getting it properly diagnosed. If a patient came off the street to my clinic I would refer them straight away to a neurologist.
I know you say you can't afford the bills but if by chance it turned out to be something serious, particularly if something can be done about it, you could miss an important opportunity. I think you should consider making this a high priority.