:blush:
Saguaro are a protected species and take forver to grow to anything looking like the stuff you see in th emovies.
Barrel cactus are readily available but tbh pretty boring unless you get them to flower, the more interesting ones are things like the chamaecereus varieties, which I get to flower much easier too. Opuntia are liked by some (prickly pear) but they can get a bit out of hand and some of the thorns (as opposed to spines) are savage if you have kids (thelocactus are much generally better in this respect as the thorns are protecting as opposed to aggressive).
easycactus.co.uk is a good place to start off for plants.