Dh and I do this.....he was called to look at cars at a car show-they paid $125. I just did a group on bread, that paid $60, and in two weeks doing something for a teacher group....I'll be paid $100.
The money always goes into our vacation account.
We're lucky in that respect....there is a big market research group here locally. Dh and I do 1 or 2 a year. Not alot, but usually adds about $300-$400 for our vacation fund
Julia