When accepting a favor would impose a financial burden, I usually push back twice and then relent. (1) "Are you sure, I can absolutely get this?" (2)"It's really not a problem, I don't mind paying." If they're still insisting at this point, I'll pack down, especially if it's obvious they're trying to do a nice thing.
I used to be more reluctant to accept that sort of help from folks, but there's a quote from the Thomas Covenant series that goes something like "in accepting the gift, one honors the giver." It's kinda stuck with me since I read it; let people give you gifts, it makes them feel good. Graciously accept, and think about how to pay it forward/back.
Couldn't agree more. I grew up poor, and I've been lucky to find a well-paying job in my adult life. It makes me feel so good to be able to do the things for people that I couldn't do when I was younger. I love that quote too - that's totally true for me. I think I get more satisfaction out of being able to offer something than the person actually receiving the thing.
As for financial stuff, if I know I do better than them, I die on the hill and insist I do it. If I know we’re the same level or if they do better than me, I do two passes of the awkward dance before giving up.
Ask yourself if it's ego stopping you from accepting generosity. Here's an extreme example:
I visited my dad in another province (parents separated). We went to a department store, and he forgot his wallet in his car. I offered to help, and he got extremely upset, lectured me in the middle of the store, and left me standing there waiting for him to fetch his money. He wouldn't even take a "you can pay back me back after we're out of here."
It was honestly insulting to me, being shut down like that. I think I hurt his pride? But it soured my opinion of him.
If you've got good will and trust, take help gracefully, then offer it back when the time and means are right. People will remember how you react to these things, and if you consistently reject them, they will eventually stop offering, even when the time comes that you really need it.