Is it bad if you give up on the quest every once and a while? Are there any negative effects?

No, there isn't any negative effects if you quit :). Usually you will come across quests that are expensive, but nothing bad happens if you cancel it.

Ok thanks. Yea Ive had a few that are too expensive and just quit lol.

;; the only quest that has 'consequences' is item hunt. if you quit out, no matter the level, it sends you right back to level one.