After being in a similar position when I was younger, I found that an active preamp is the first place to start, as most mm style pickups give a relatively sufficient stingray sound.
Preamp wise, the retrovibe one is probably the best and most cost effective one to go for, as it uses the stingray preamp schematic, but uses cheaper parts, hence the lower cost, though looking at them now, theyve jumped up in cost, as I used to see them for £40ish. The cheap 2 band Chinese ones tend to boost the volume too much and can distort the amplifier too easily. But can give you a rough approximation towards the sound.
Pickup wise, if you want close to the stingray sound, go for any open pole (ie the magnets are on show, like the stingray) mm shaped pickup. Try and find one with a resistance of roughly 8ohms, as the lower resistance get closer to the sound you're after. Ceramic pickups (that have magnets on the bottom of the poles, found mostly on cheap chinese pickups) work okay, but the alnico ones (no magnet on the bottom) get you a bit closer.
As an ex poor teenager RHCP fan, I hope this helps get you where you need to be.