Get a used one on eBay! Good linear power supplies are super old tech and are super robust.

Some pedals draw power more unevenly then others, which can cause a "buzz" on the power supply output. If it's just one supply and one pedal, and it's designed to work with a little buzz on the supply, you won't notice it. But impose that buzz on other pedals with shared power, and the buzz might make its way into the audio signal path. Isolated supplies let pedals do whatever they want with their own power supply channel, and the power stays clean to the others.

Ultimately, you don't need to solve problems you don't have. If you try sharing a supply with your pedals, and they work well together, then they're is little benefit to an isolated power supply. A power strip of power supplies is a totally valid way to have isolated supplies, too (albeit harder to manage and might be less space efficient).