A high-capacity portable power station keeps your gear running through outages and weekend trips, so you want to buy one built to last ten years rather than a cheap unit you will replace in two. Focus on units with LiFePO4 batteries, which handle thousands of charge cycles before wearing out.
Tech brands usually drop new models in the spring, which means retailers heavily discount last year's version during major shopping events like Prime Day. Wait for those sales to grab top-tier gear at a steep markdown.
That 18-month window is a hard deadline, not free money. If you still have a balance left when it ends, you will get hit with interest on the whole original amount.