Mold we used: $25. as of July 2021.
https://www.amazon.com/gp/product/B07HMKMY2Q/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Pyramid Mold - comes with 2 silicone pyramid molds, & 1 plastic base to support it.
FYI, in case it matters to you, the MOLD is 6", but the pyramid formed will be 5.75". not the full 6" . It's a fairly thick mold.
Resin we used: $25. as of July 2021.
https://www.amazon.com/gp/product/B08L943QYB/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
After Much searching, this was the best overall deal on the resin I found - at the beginner volume, to see if you like working with it.
The cost does not drop significantly until you go up in quantity of purchase to a gallon or more. (Ie, a gallon costs $64. = $0.50/oz, but most quart size kits costs about a buck an ounce).
This kit was 35 oz total, with a lot of extras, for only $0.70/oz. Even if you don't need the glitter, etc, just the gloves, measuring cups, etc is worth getting. You probably don't have those things, and you'll need them.
Just be careful on the measurements. They have ounces marked clear enough, but on the back, they seem to have centimeters and millimeters intermixed, and I wouldn't trust those, unless you know what you're doing. The lines are very fine, so I literally drew over the ounce marks I wanted to use with a sharpie, to ensure I didn't mess up.
Mixing the two parts equally is a big deal, so it matters.