fortunately, I ordered SS using the B1G1 50% off glitch so I only ended up paying $17.50 w/tax for it. I don't know that it dropped from it's $35 or not like BvS did (down to $17 on the 29/30th day, just got in the 30 day elite window IIRC).
I don't recall any Marvel SB dropping to below $25 at any point in time before they sold out.
I did as well, best decision I made on getting the SS SB as I'd be hard pressed to get it at $35.
Several of the earlier Marvel 3D steels were sold for $19.99 at release. The most I have ever seen Best Buy sell them at release was for $27.99 and that was for the most recent ones (Ant-Man, etc).
Avengers: Age Of Ultron was $19.99 at time of release. Thor 2 was $22.99, the rest were primarily $24.99 at time of release. Most recent ones, yes, they were $27.99 at time of release.
The $34.99 at time of announcement is a bit of a PITA, without question. At least BB is offering a non-3D SB as a second option, like they've been doing with the 4K / non-4K ones they've done with Huntsman: Winter's War and Jason Bourne.