@tsarstepan,
I think the limit for asking guest to pay for the party is to BYOB, which according to Punkey, had already been done.
That's understandable, as alcohol is expensive, some will choose to drink more than others, their tastes are different, etc.
When I go to dinner at someone's home, I bring a host/hostess gift, preferably something that will be enjoyed by all during the dinner, not necessarily food. I generally bring a small desert type thing (secondary to what may be served), a wine I know the host enjoys, flowers, nuts, cheese, etc.