I live in Thailand, and got an advertised promotion for Spotify premium for less than half a dollar for three months total. Credit card usage and online payments here are pretty low though, so that will surely lower the speed of adaptation.

how easy would it be to VPN to a LA country, signup for the plan and then just have service for $1.5?

Probably not very hard. The biggest headache is probably that the recurring credit card purchases might be flagged and blocked for being an unrecognized international transaction. But then again, $1.50 won't raise alarms for many banks.

Don't they know the country where the card was issued? I.e. Spotify could refuse payment using non-LA card? Or, ideally, just bump it to the higher bracket (with appropriate notice).

Playlists are completely different. Already had this within Europe, if you like music in a country you should sign up for Spotify in that country. Music availability can also differ.

So could be possible if you like music commonly listened to in Latin America and don't use Spotify's playlists. Otherwise I'd pay more to stay with the service of your home country.

id assume the catalog is different by region the way netflix is, so you might not get the music you expect for that price