I'm pretty sure $3 is just fine. +2 Cards is not so hot, and +2 Actions without draw is a terrible way to get a Village effect. Steward and Squire each offer these exact choices amongst stronger alternatives (trashing for Steward, Silver-gaining and a bonus +$1 for Squire) at the same or cheaper prices. It therefore follows that a $3 card can offer these choices amongst weaker alternatives and still have room for a flat +1 Buy.
The possibilities break down roughly like this:
+2 Cards, +1 Buy - That's probably a balanced $2 card, but it would not be a popular one.
+1 Card, +1 Action, +1 Buy - Probably too strong for a $2 card but strictly weaker than Market Square at $3.
+2 Actions, +1 Buy - Not strong enough for a $2 card.
That adds up to a $3 card in my book. Certainly it would be a pretty terrible $4 card. Of course there's another test here, the real separator between the $3 and $4 cost tiers: is it unbalancing to open with 2 copies of it? Pretty sure you'd be fine: playing two Copies in a row either leaves you:
* Down two cards, with 3 Actions and 2 Buys.
* Down one card, with 2 Actions and 2 Buys.
* Same handsize, with 1 Action and 2 Buys.
* Up a card, with 0 Actions and 2 Buys.
Those seem far, far shy of overpowered for a combined effect on turns 3-5.