There are two struggles I face answering this question:
1- The best time to purchase things is through a Kickstarter campaign as by this time I know how many people are interested in the designs of my products and I can have a better estimate as to their success after the fact. ALSO: If the designs/my product doesn't fund at all, the answer is no... these items will not be available after the Kickstarter as not enough folks supported it!
2- I always give Kickstarters the Best Deal. These pins specifically are going for $15 each on Kickstarter (with a bonus deal at $100 & eventually at $200) but the same pins will be $20 on the shop afterwards to accommodate further production costs & future re-prints!
Long story short: I try to make my work available to the best of my ability because I know sometimes folks are in a bind. However, the best support comes from Kickstarter campaigns and allows me to plan better <3