Anal sex or toys?
If you have no personal experience with anal toys, get yourself some water based lube and try a finger or two a few times to see if you like it before you buy any toys. Try to relax when you insert anything because it won't be a pleasant experience if you tense up. I would do this alone, you don't want an inexperienced partner ramming anything in there.
If it's something you want to continue doing, start looking for some toys. To make it easier to choose the right toy(s), you can narrow your search by selecting certain criteria (length, circumference, etc) on the left side of the page. Also, be sure to read the reviews for each toy that interests you. If you choose to purchase a toy, I highly recommend looking at only toys that have a nice base on them. You don't want to be losing anything up there.