Magical Vehicles!

[Coidzor]

As I recall there are no first party rules on the subject. There are some vehicles of defined cost and nature, but they're well out of the price range of a 4th level party, even if you had your entire party's WBL in cash and pooled it together.

D&D 3.5 also lacked much in the way of first party rules, though you could half-ass something with the Stronghold Builder's Guide's rules for mobile stronghold spaces.

If you were fifth level then you could do something with retraining and get Craft Construct (or I think just go from Craft Poppet to Craft Construct at 5th level?).

24,000 should be about your total net worth as a party of 4 fourth level PCs.

Ostensibly a Huge Animated Object(the size of a Wagon) costs about 12,500 gp to make, 25,000 to buy. Half your party's WBL just to make it puts it still outside of your price range, I'd say. Not without some kind of huge windfall or your GM basically just giving it to you or having some kind of sidequest just to get it or something.

Alternative pricing would give you 100 gp for a Huge-sized Wagon and 5500 gp to make it an Animated Object with 4 CP, which is much more affordable, but it'd still be too expensive for any single one of you, and would take up about 23.3% of your party's wealth. I believe with 4 CP you could invest all of that into a land speed of 70. Alternatively you could give it a Fly Speed and pump that fly speed up to 60.