I'm not talking about a major life change, but something that you use frequently and really didn't cost much. Here are four I use almost every day. I can't imagine not using them now.
Shavewell Fogless Shower Mirror, $12. It's so much easier to shave in the shower.
Ninja IQ Blender, $59 on sale. I blend my coffee with it every day and make smoothies most evenings.
Bodum French Press, $16. I started making coffee with a French Press 15 years ago and never looked back.
Timex Tapscreen HRM watch, $60 used. I bought one of these watches about 7 years ago and loved it. When people couldn't figure out the secret to using the tap screen (fingernail taps), these $120 watches were dumped on eBay and I bought 4 more, usually in the $60 range. It's my go-to running watch.