The middle route from Columbia to the Grand Strand takes you through Manning on SC-261. US-521 joins 261 there, and they run together until just east of Manning where 261 forks North to Kingstree and 521 continues on to Greeleyville.
Historically rest stops between Manning and Greeleyville have been pretty sparse, so perhaps that's why I especially noticed this rather lavish little gas plaza when it was constructed just a few years ago a little East of the 261/521 fork. That, and the fact that any sign with the word "pizza" on it tends to concentrate my attention.
While the right confluence of events hadn't ever happened, I figured it was a pretty sure thing that sooner or later I would be stopping at Tanners. Well, that was true, but not for the reasons I'd anticipated -- I noticed earlier this year that the place, which had started on such a large scale (this wasn't your typical no-name, one-guy, rural convenience store) so recently was well and truly gone.
I don't know if it turned out that US-521 wasn't as major a road as they had figured, but even with gas, pizza, bait and an attached liquor store as draws apparently the traffic wasn't there. LoopNet on the other hand, says they cleared $78,000 and 100,000 gallons monthly, so who knows?
At any rate, the road between Manning and Greeleyville is pretty empty again.
UPDATE 23 May 2012: This store is to re-open today under new ownership as an Ezshop. See the comments.
UPDATE 20 July 2012 -- Pictures of the re-opened shop: