Player since 2015... never traded before.

I've been playing this game since 2015 (have the title) and have never traded. How do I know what is good? I have always maintained 1 of each item, trading doubles to get better items. I have so much stuff!!

I was hoping to do some trades for different goal explosions but have no idea the value of anything at all. It's also mega slow on PS5 to select and type to someone. Any advice on where to start ?

Edit: Oh. Lame.

Why are blueprints so stupidly expensive. I have hundreds.