Forget about prepaid or debit cards, they do absolutely nothing to help grow your credit.
There are a couple of good ones that you might look at ..
Discover It secured card. You cannot directly apply for the secured card, but if you apply for the regular It card and you're denied then they may offer you the secured card. The secured card typically graduates to unsecured in about 12 months, it offers rewards, you get your TransUnion FICO score for free each month, no annual fee, doesn't report as a secured card. The interest rate is high, like with most secured cards, so be sure and pay it off in full each month to avoid paying interest.
https://www.discover.com/credit-card...DR_ALLPS_CC_IT
SDFCU (State Department FCU). This card won't unsecure, there is no credit check, no annual fee, it has a low interest rate, it offers some rewards - I'm not completely sure how it reports but I
think it doesn't report as secured.
If you don't qualify to join the CU under their regular terms then you can sign up with American Consumer Council (ACC) and that will qualify you to join SDFCU
https://www.sdfcu.org/emv-creditcards
As for how much to put on a secured card, $800 isn't bad but getting it up to at least $1k would be better - since it would take it out of the toy limit range (FICO and other creditors really don't like seeing toy limits).
edited to add - When people apply for secured cards, they will often get the 5+ day notification comment instead of being instantly approved, so don't worry if you get that notice. If you 'are' denied then always call and ask to speak to an underwriter, then ask that person to reconsider your application - many, though not all, have been approved, for either secured or regular cards after being denied, by asking for a reconsideration.