The three things you should buy are . . .
1. Movie tickets. In the summer, lots of movie theaters offer programs that let kids see movies at discounted prices. So check with your local theater to see if it offers a program like that.
2. Swimwear and lingerie. Victoria's Secret holds its semiannual sale in January and June, and lots of other retailers follow their lead. So it's a good time to save big on swimsuits and underwear.
3. Gym memberships. Gyms are more eager for sign-ups at the beginning of summer, so you might be able to negotiate a better deal.
And two things you shouldn't buy are . . .
1. Grills. Since summer officially starts in June, the higher demand for grills means higher prices. But there should be more sales later in the summer.
2. Designer clothing. The prices are better in July.
(Nerd Wallet / Nerd Wallet)