Gas bottles

We have both gas and coal BBQs.  We bought our gas bottle from the petrol station (Disa) they are quite small bottles (any larger and you have to have a licence/permit from the Ayuntamiento) but having said that, our small bottle has lasted well and is still going strong!  I think it was about 40€ and as in the UK, keep your invoice as you may need this so you can exchange it when empty and not pay the full price again.  Hope this helps.