Re: Seeking idea for $50-$100 small business services or products to offer.
Offer to liven up their facebook pages. Find "hot" articles and pics, etc. and post to their FB page to increase their "engagement" factor.
Do it for a week for free, then, if the results are good, have them pay you $100 / month to keep it going.
PS: Many (MOST!) biz fanpages are "dead." They tried, but gave up eventually.