This is a little different from the others on this list, but a lot of DIY stuff for parties/weddings. The money you're saving is negated by time lost, not to mention unless you have unlimited time/ no job and are able to thrift everything, the components for DIY aren't that inexpensive. For my sister's wedding, we did everything ourselves. Everything from literally painting the venue, collecting/creating every table scape, my dad built the stage and dance floor, all the way through setting up the hundreds of little desserts on the day of. It was all wonderful and lovely. And took a massive amount of time and labor across several families. When you factor in the value of people's time, it was not less expensive than mine. We rented everything and it was so nice not to stress about dressing every corner of the room or decorating the bar, or making sure we didn't run out of ice on the day of. We still chose super frugal options because the wedding industry is a scam, but we just paid for everything.

Sometimes it's worth it just to pay people to do stuff. Value your time and mental health more than money.