It looks like a Mammillaria, although the photo isn't very clear.
There are so many different Mammillarias, it's difficult to tell which one it is.
Maybe when it flowers you'll be better able to find out.

Mammillarias have their spines on little tubercles, that are said to resemble nipples, or mammillae. Hence the name.
It looks like that in the photo.

I also think its a mammilaria but I dont know which one.

I thought mammilaria too at first, but then wasn't so sure as the tubercles seem to be arranged in vertical rows rather than spirals? Definitely one you need padded gloves for!

It is difficult to see due to the poor lighting (grow lights) and all the spines but they are arranged in vertical rows. They didn't seem that spiny at first but they are like fiberglass or Opuntia where you don't notice the spines until there are hundreds in your hands! I've been trying to find it but there are too many species too look through.

It's very difficult to identify a cactus. There are so many different ones, and also a single species can look different according to the conditions they grow in.

After enlarging the photo I can see the spines are in vertical rows, so that leads me to think it is a type of Echinocereus, or a closely related group.

Maybe you'll be able to identify it when it flowers.

Thank you for the help, it does seem like waiting for the flowers will give me the best shot at figuring this one out. 90% of the indoor plants I buy don't come with tags, it would be nice if they could at least stick a name tag in the pot.

Like here ... I bought a cactus a few months ago and the label said "Cactus" ... lol !

The likeliest candidate to my mind is Echinocereus reichenbachii, though there is some question of that, since it is somewhat etiolated--stretched, due to lack of light.

Wow Hywel, I bet you were please to find out what sort of plant it was!

Indeed, I'll bet he was! I work in a retail plant nursery, and I get really excercised at some of our suppliers, with their "Cactus/Succulent, Asst." labels! Many times, I can rectify that, but I really don't have the time, and a large minority are difficult to identify reliably, especially in their juvenile, greenhouse-grown aspect. Oh, well! : /

Orange flowers have started opening and does look like mammilaria now. I'd like to know which one but am satisfied knowing that much for now!

Wow! Send us a picture, please, Rkwright! Orange-flowering Mammillarias are hard to find.