AmpliTube on iOS is where you get the drum loops addons. I know they just released a second drum style pack and that is $18.99 (AUD prices) which includes Jazz, Reggae, Latin, Rock, Pop, Metal Blues and Funky packs. I assume the first pack of similar styles cost me the same. It really depends on what you want to do and where you want to do it.
I've spent probably about $100 or so over the years on AmpliTube for iOS (I've been using it since 2011 at least). I have almost every add-on the app contains. I am a big fan of their tone. I can record very decent sounding songs using just this app. It's not a complete package, but it's pretty damn close. Connect it to a DAW like Meteor using Audiobus and the sky is the limit.
For PC or Mac though, you'll need a DAW like Reaper and the VST version of AmpliTube. PC/Mac is more versatile and you should be able to produce more complete and professional recordings. Or you can combine the two.
Check out Evangelos Koudonas on Bandcamp. He records all of his guitar in iOS and then mixes it all (using GarageBand for drums I believe) on the Mac. There's more to it than that, but he really shows what is achievable. Plus he's a great musician and person
Excuse my ignorance, if I was to use amplitude to record my guitar parts and use the drum loop facility to insert my drum patterns, what would Meteor enable me to do? Meteor is another recording app right? So why use both together?
My brain aches!