Tell you a little story with a point:
I have been doing concrete for a lot of years, and evolved into doing concrete roofs and decks, several underground and earth sheltered home, and so on....and I rented my shoring from Ellis Construction Specialties in OKC....they always gave me engineered plans for the shoring post layout, but what I hated was paying rent...and I had 4 weeks, and then I would get another 4 weeks whether I kept them that long or not. 5 weeks of weekly rental was the same as 2 months....but anyway....and I didn't like wooden shoring with Ellis clamps...
So I started running a search with "Search Tempest" that constantly searched Craigslist and looked for "shores" and "shoring" and Shore posts" and "Ellis Shores" and after just a few months, I had a hit in Houston...guy had 300+ shore posts left from someone he shared his location with...he knew what they were, but he did flatwork, and didn't want to move the posts....he was asking $15 each, and I said, if I take all of them? He said if you are here in the morning before I leave to the job site, $10 each for all.
Needless to say I hauled ass for Houston with cash in hand, and pulling my trailer, and came back with 305 10 foot posts and 35 - 14 footers. 4 Pallet carrying racks...and they were full. The posts sell in OKC for $116 for the short ones. And these were like new. Oh yeah, these are the good steel shores with a screw collar to raise them..last a lifetime if cared for.
The next job I was on, I used all but maybe 3 of the posts, and had I rented, I would have paid nearly 4k for 2 months...plus delivery...as it was, I cleared them on the first job.
So make a plan, and then look and be prepared. The guy I dealt with told me he had several calls, but since I called him first, and told him I was on the road with cash, he held them for me. Deals are out there....but, when the economy is rolling, they are hard to find. But if I were looking for forms like you seek, I would be on search Tempest and set it to check every day, or twice a day, and it will look online and at eBay also. I have seen lots of forms in the past for sale, with trucks and crane trucks to move them...so that tells me that either the economy slows and guys bail, or this is less demand for poured walls, or,....insurance costs drive a lot of smaller guys out.
Most of the residential wall form work here is ICF now...commercial is where you see the poured walls.