Single cap: $15 for my F2 Red
Full Set: $15 or $20 on my Graphite set.
Unless you count my sets coming in pieces, then $15 for some semi-used WoB Cherry DS's and then $30 later when inlikeflynn sold me a set of 1.5 modifiers and spacebar etc(after a few months of searching). In which case I had spent $45 and then gotten a red Cherry escape from CPTBadAss as a Secret Santa gift.
GB set: Hashbaz's RGBY and Faux Cherry escape GB in which (if I recall) I spent just a tick over $30 on one set plus a faux Cherry escape.