There's always a coupon for 10% off. I'm talking about one of those 25% off or free shipping deals they had last summer and winter. And I'm getting the feeling they've retired those.
Getting the Foom set may be fun in a "first kid on my block with the hot new toy" way, but again, there's no price difference from buying them separately. There were also people paying major bucks to complete their Blobs, Annihiluses and Ronans when they came out because they couldn't bear to wait a little while. Yet fast forward a few months, and those ML series were still sitting on pegs or getting clearanced.
In other words, don't fret too much. You'll be able to get Foom later if HTS doesn't re-stock the exclusive.
Well 10% off $120 is a lot. Plus Target had all of them here 2 weeks ago. They certainly were not at SDCC before anywhere else.