I think I can honestly say, I have never purchased anything that saved me money in the long run, except paying off ALL my credit cards and never using any Credit Card again. Have not used a true Credit Card in over 20 years at least. THAT was the best thing I could have done. No interest!
We have a second checking account with a nice balance in it. When we need to purchase a high ticket item, we use that account. We then pay back to that account with regular monthly payments (plus our own interest rate). As a result, we get our own interest, not some credit card CEO for his Christmas bonus. THIS pays for itself and then some!