$500 would get you a new Model 94 in very good to excellent condition from that era.
Worst case, Midwest Gun Works lists a complete lower tang assembly (with the lower tang and all the fire control parts included and assembled) for $175. You need to get the correct solid hammer version for your rifle, but it's then basically a drop in/direct replacement installation. My suspicion is that your local gunsmith would do something similar, with a 100% markup on parts, a $100 minimum charge for labor and then tax to come up with a $500 repair bill.
Best case, it's the a weak or broken trigger stop spring, which is a $5.00 part from Midwest Gun Works. That's a likely problem as if the trigger stop spring does not push the trigger stop down (it's the part with the square shaped bit on the end that sticks out the bottom of the tang), the trigger will not release. The trigger stop itself is not likely to break, but it's an $8.00 part. You may want to try cycling and dry firing your carbine, then see if you can pull the stop down with a toothpick, if you can, and it then functions normally, the spring is your problem.
As for the hammer, you should be able to feel whether the sear notch and half cock notch are intact. It's possible to shear one or the other of them if it's dropped on the hammer. A solid hammer is a $75.00 part. A new sear for a top eject 94 is a $40 part.