You want a portable solar panel charging kit that actually holds up in the backcountry and keeps your gear running all weekend. Buy a rugged, weather-resistant setup once so you are not replacing cheap plastic junk by the end of summer.
Tech brands usually drop new camping gear right before peak summer, which means last year's proven models go on sale. Look for the older version with solid reviews instead of paying extra for minor upgrades.
Remember that the 0% intro APR for 15 months on purchases and balance transfers is a hard deadline, not free money. If you still have a balance left when those 15 months end, regular interest kicks in on the whole original amount.