It takes time for a set to go out of print and for the supply to shrink, which is what ultimately drives up the price
Graded Population Report: Dragapult ex #200 Visualize the distrbution of grades in the chart
Let's review, it's 4 power on turn 3, check, cost reduction for any spell, check, and scales up with a good portion of your deck, you bet you should build in more such creatures
With a reasonably low Ink cost of 4 (and no option to use it in your Inkwell, as is the case with several cards on this list!), its easy enough to get Robin Hood into play
Finally the lands start getting way better, with better fixing like Drowned Catacomb, but also neat tech like Peat Bog + Saprazzan Skerry which are consistent ramp if we can proliferate and Diamond City that can store up tons of shield counters and then activate it reliably thanks to Venser creating creatures so easily