Are you casting something in clear resin or going to simply color the resin and mix it?
If you are coloring it - I am no expert, but personally, I would just go to Hobby Lobby or Michael's and purchase the PR. Find a 40% off coupon for the PR and save some money. All you really need is container to hold it while it sets (I used a glad sandwich container for my first few pours), a container to mix it in, a dye or coloring agent (also get a Michaels/Hobby Lobby), a way to stir it, and don't forget the MEKP - you have to buy it at both of those places I believe, and gloves. While a kit is easy to order and convenient, I never feel I get a good deal in kits most of the time - Plus I would rather throw my mixing glasses away, so I get cheap disposable glasses -
Try a few rounds, and if you get bit with the casting bug like many of us have you will go through a kit in a matter of a night....
just my $0.02.