Part of saving money comes at timing your purchases correctly. If you don’t have time constraints, buying objects out of season will significantly help your cost savings. Of course, you’re sacrificing selectivity and the “new / in season” products.
Here’s a website that categorically and thoroughly lists things to purchase at specific times: http://www.freeshipping.org/blog/best-time-to-buy-guide/
Additionally, Lifehacker made an awesome infographic that is less comprehensive, yet still helpful.