I'm looking to produce an ad for a halloween ebook I wrote. I'm just wondering if it is worth put any money into.
No it is not. Unless you are a big name you place yourself next to strong competitors that are supported by big budgets. Start small with friends, friends of friends, get reviwes, create a blog become known and maybe spend some money with FB ads. If you have the budget print some copies and fight for your space with readers clubs etc. It is a tough business with a lot of competition and therefore you must work in order to be noticed .