Slo, I agree wholeheartedly with tony re harbor freight and solar. Overpriced and, IMO, junky. I've not bought from solarblvd myself but have had them recommended.
FWIW, many years ago I had two of those panels used in the HF kit. After about 3 years the output had fallen by almost 1/3.
The solar blvd product that tony linked to are much better panels, IMO. That they already fold up is a bonus. All you need to complete a charging setup is a charge controller and some wire. A CClike this would handle that panel set nicely. Those guys also sell Steca which are very good. You just need to make sure the CC can handle the maximum amperage & voltage output of the panels.
Even amazon.com has better deals on PV than HF. They sell a lot of Renogy. FWIW, Renogy also sells from their own website; prices are about the same as amazon but amazon has much better customer service. One of the main reasons I buy a lot from amazon is their service.
Amazon has a 100 watt kit for under $180 right nowfor example. It does not fold though. This one does fold; costs more but still under $250 with CC. I believe shipping is free on that.
FYI, the cost per watt is much higher on small panels like the 15 watt ones in that HF kit. The larger the panel the less the per watt cost.