MT3 is exclusive to Drop, so yea, get ready to pay the premium.

I do note Amazon sometimes has them, and my local Amazon had the Sulawesi Mt3 for quite a bit cheaper than Drop's website, so you can take a look there.

First I was "120$ for a keyboard? Sounds very reasonable, I did my 75% build for about the same" but then it hit me that it's just keycaps.

They do look great, but that's very expensive, wow.

Drop is one of the rare shops that don't run group buys, but have in stock items instead. Mostly. No need for fomo unless stated otherwise on the product page.

Also, they have at least one buy-one-get-one-free sale per year. Because of that, you have a good chance of getting one second hand for less than a new one.

Regarding kitting you have to watch out for modifiers in the correct size for the correct row, but most keyboards are fairly standard with the exception being the bottom row. Check Shift, Ctrl, Alt, Space and Fn/Win for correct size.

I haven't tried the profile. Do you think it's for you? I think that's important to think about. If you don't know if you like keycaps with dished tops, maybe you could try some other, cheaper variant first.