Hi Austin
Welcome aboard!
I bought a LiFePo and charger from Hobby King a few years ago, but that is not helpful if you are struggling right now.
Chosing an alternative will depend rather on how you want to use it. The internal batteries of an FT817 / FT818 are often scoffed at, but they will give you an hour or two of activation, depending on mode etc (heavy drain on FM, less so on SSB or CW). I’ve done three activations in a day without a recharge whilst on holiday and not wanting to carry extra batteries…
I notice that from this Thursday 7th May, Lidl are selling 12v 4AH Lion battery packs for their electric tool range for UKP 14-99, and a charger for UKP 12-99. It’s probably not an ideal shape for carrying around, and you would have to arrange some safe, fused, connections, but might be worth a look…
Or you could go low power CW and run on a PP3 
73
Adrian
G4AZS