This is why I went back to see what I did for TFSS 4.0 (an exclusive combiner, back then it was seven deluxes and a Voyager). Double checking, I made a mistake in my initial posting, but I still think they're roughly comparable. Except they didn't have a lot of 'new' weapons, mostly Bludgeon's swords recycled from a dragon Optimus, and recolors of Scoop's targetmasters. And they were all just repaints or head-remolds. It was $297 in 2015. So $299.99 isn't that bad, and honestly a bit better if you consider they're new molds (sharing some parts between members of the set, obviously), with their new-mold animal buddies. It's really NOT bad if they do the all-new-mold extra figure, the weapons, and the base. I do agree it's expensive, but it does fit with prior offerings and actually improves on the package a bit.
I plan to get just ONE, for myself. The problems with planning for resale is that you have to hold onto it for a while, if you open it to see that all parts are there people will complain it's not 'MSIB', if you don't and something's missing, they take it out on you for not checking even though you couldn't without opening it, and Ebay takes a bite, shipping takes a bite (especially for a box this big), etc. Resale of toys, which I've done for years, has been a diminishing return...