I'm not a musician, but I just bought a used Fender Stratocaster. I'm looking for some kind of wireless device to plug into the guitars jack that uses 'bluetooth' or something similar to play the guitar on a bluetooth speaker. Can you help?

If you're looking for a Bluetooth instrument cable for your non Bluetooth amp, you can try the Line 6 G10

Try Blackstar mini amps. They have one like that.

They have wireless setups for electric guitar. Be careful what you choose however, some of the cheaper ones may not have the best connectivity. Like they always say, you get what you pay for.

You looking at 200 dollars or more for that find a equivalent in ebayit would be called blutooth 1/4 guitar jack search that ob ebay