Bands get shit all from record sales, they money is split up into the percentage the artists get, what the record label gets, what the manufacturers and distributors get, what the publishers get, what the store selling the album gets etc. The shitty thing is that the recording advance that record labels give to bands is usually paid off via those royalties and shit that the band receives from the album sales. So it's very rare for bands to make money from albums, although it's not unheard of.
The biggest way bands make money is from touring - so go out, buy the tickets and buy the merch. However, you still have to buy the albums if you're that intent on supporting the band, because bands can't really sell tickets for concerts and go on tour if their albums aren't selling. It'd be a complete waste of money and an extremely high risk I'm sure no promoter would want to take - taking a band on tour that aren't selling any albums.
So they still have to sell records if they want to sell concert tickets.
Plus they'll usually go to where fan demand is high.
I.e. countries where they've sold the most albums.