A place out of Memphis, TN: $1325 for a 2 liter with
under 70K miles. 98+% customer satisfaction rating. They state they truck ship for $150. One year part warranty. Additional warranties available. They state the engine comes
with intake and exhaust manifolds too. If you can do the swap yourself, you would be in it for +/- $1500. If you have a mechanic shop swap it out, you'd probably have to add another $600-$700 to the total cost. Probably give you a better leg to stand on if you encounter a parts problem with it.
Now... was
this used engine taken care of (the oil changed regularly with the
correct type and amount of oil)? I don't know.
On the other hand, most garage/shops would charge you in the range of $1500 just to machine and rebuild the head, clean out the oil pan and replace the timing chain and components on your engine... if that was the ONLY damage to the engine. Chances are if the timing components failed at 90-100K your truck was probably rode hard and put away wet more than few times with little required periodic maintenance.
http://cgi.ebay.com/ebaymotors/Engine-4Cyl-2-0L-2003-2004-Chevy-Tracker-/250394708812?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a4cb00b4cX2 on using partsdinosaur for replacement parts. Reasonable prices and decent quality. User friendly service too.
You could probably get $150 out of the sale of the extra exhaust manifold too. The exhaust manifold on these 2 liter engines are built like a shorty header and made out of tubing versus a cast manifold.