So, Dominion has several cards that can gain Treasures directly to your hand, but nothing that gains Actions directly to your hand. And I'm sure there are all kinds of card-balance reasons for such a card not to exist*. But I bet none of them is the following:
How would such a card interact with Nomad Camp, rules-wise?
Discuss.
*That said, I wouldn't be surprised if some card in the following family—which I'm certainly not the first to propose—were balanced:
Swap Meet
Action: ${A}
+1 Action
{B}
{C} a card from your hand. {D} gain a card costing {E}, putting it into your hand
...where:
{A} is 5, 4, or 3
{B} is +$2, +$1, or nothing
{C} is "trash" or "return to the supply"
{D} is "you may" or nothing
{E} is "less than it", "up to its cost", or "the same"
...but I couldn't tell you which version is the good one.