u/1984JLS

I am building a new race bike for my daughter and I need good solid sources for finding used parts. Ideally, I would like to be able to save searches and hit every source's site daily and refresh or hit the saved searches button to see if anything has been posted. I am not necessarily in a hurry, but I don't have time to look for an hour every day. I know the specific parts I need. I'd really like to look for just that, but wading through everything else can be exhausting.

I know about Pinkbike, Ebay, and fb marketplace. Are there any other good sources?

I am in the USA

I've built several generic carbon frame bikes (Chinese frames). All have been fine with no issues.

I was wondering if there are generic frame options for e mtb, and if the motor/ drive systems can be sourced separately.

Only reason to consider is just saving a little money over the big box brands.