It is unfortunate, but there are schemers out there who would be happy to rip you off.  Still others offer services that simply don't live up to the promise.  We will try to list those that simply aren't worth it, or those that should be avoided at all costs, here.  You deserve an explanation, too.

NewsPaperArchive.com 

This is a legitimate and worthwhile site, EXCEPT...  The only newspapers they have are those that subscribe to their services for archiving. The problem is they are not the only game in town and the coverage [numbers of papers they archive] is low and hit-or-miss.  They have next to ZERO coverage of NJ for instance.  Coverage of PA is sketchy, but coverage of Gettysburg, York and Adams County PA, for instance, is OUTSTANDING.  The situation I had was that I got what I needed for my research needs at the time and did not use it the rest of the year.  THEN they auto-renewed against my credit card.  They were nice about fixing it, though.

I must be honest...  If they have the newspaper(s) you need, the service performs very well and is easy to use.  Some of the newspapers they feature are also on Ancestry.com, but are much harder to find there.  

FOLD.com

Incredibly niche service w/ military-only focus.  Nearly everything seemed to duplicate what could be found on Ancestry.com or FamilySearch.org [free].  I just didn't "get it"...  Couldn't see how it fit in for the extra $.... 

PublicRecordsChecks.com

This is the only service I actually threatened to go to the authorities over...  They promise you hundreds of hits and deliver nothing you haven't seen before...