It's $35 to renew or if your not an Extra yet you can upgrade without paying the fee after passing the test.I got a renewal 'reminder' from a Texas amateur club via email. Came about two months out. Quite random, but appreciated.
Never had a solicitation from a renewal business, but I've done all of my FCC stuff myself.
To some people, it might be worth the 3rd party fee to avoid the hassle of dealing with the FCC's site.
If you are patient, you can renew on your own using the CORES system. The single biggest issue I had at the FCC/CORES site when I was renewing is that you MUST use the site's navigation buttons. If you use your 'back' button, it will kick you out of the system and you've gotta log back on again and start from the beginning. Old habits die hard...I found.
I've bought from Mouser several times and have been pretty happy with them. Only negative is their search can be confusing if you aren't positive what you are looking for.You might check at Mouser Elecronics or JameCo.