Maybe check if there is a community bike workshop where you live? I have 2 in my city and it's great, you can buy parts from them at cost, they also sell used/salvaged parts and you do the installation yourself. They have all the tools and guidance you need, you'll save big on labor and you'll learn how to fix your own bike.
In my city, used rims with spokes (may need to be trued) go for about 10$, gently used tires are free and a tube is 3$.