What I've used from US that's sufficient.
404 tooling resin
Black Tooling Get Coat, or Orange , whichever your prefer. I prefer black, you can see if you have any air bubbles in the glass a lot easier when laying parts in your mold.
1.5 oz Chopped Strand Glass
If you go to the US Composites website, and click products, then Polyester Resins, all of the gelcoat, and resin are on that same page. They're online ordering system sucks, anything I've ordered from them, I've just called down and done over the phone. They're exceptionally nice, and ship things pretty quickly.
The resins come with MEKP, those are all you'll need to build your mold. Product numbers vary, depending on if you're buying a quart, gallon, 5 gal, etc. If you're just building one mold, a quart of tooling gel will be more than sufficient, and you'll probably want a gallon of 404, give you more than enough to build your mold, and a few parts out of it.