The last "major" purchase I did on Amazon was my electric toothbrush (which I love by the way) I purchased it solely with gift cards I received either as birthday presents or side-gigs (primarily surveys). I thought that this was a very interesting experiment since doing so allowed me to not get excited about the next newest and fanciest toothbrush, but allowed me to see all of the features, really look at the reviews, and evaluate what I wanted from it and what it was capable of.
Now I'm doing it again. I am currently saving up Amazon gift cards to purchase a garage door opener. The garage door opener I am looking at is approximately $200 to $250 and I have already saved up to $80 in the past 2 months going about this slow route. Approximately $60 was from credit card cash-back and $20 was from surveys. I imagine that my credit card cash back feature will end up being the main contributor to my goal. While I know the cash back isn't necessarily free money, in fact, I have to spend a lot of money to earn that money, it is money I would have otherwise spent and was returned back to me, so for this purpose I'll consider it "free.” I'll keep you posted on my progress.