Autism Tests: Recommendations Please

I'm undiagnosed [F75]. Seeing lots of discussion of testing, I Googled Autism tests. The first two I tried asked a bunch of questions, then asked for my credit card details. NO WAY! I'm ok with paying for legit stuff, but there are so many scams on the internet that I need some evidence of value and trustworthiness before I give out credit card details.

I'd appreciate recommendations of tests with strong basis in evidence (not to mention being secure).