How to fix old trumpet?

I've done a lot of budget instrument repairs for our local middle school, which doesn't have any funding for repairs. So, I have experience with "old, but don't want to spend a lot of money".

Regarding the valves:

I assume the valve can be removed from the casing. If not, you're completely out-of-luck. Otherwise, go ahead to remove the valve and the bottom cap. There is probably some gunk (grease plus dirt) stuck in the valve casing, mainly where the tubing enters the casing. No amount of oiling will overcome that problem until you manually clean out the gunk.

Get a valve case brush (or any other cylindrical shaped brush which fits) to scrub the casing. Use hot water and dishwashing detergent on it to get all of the oily residue out. Then dry thoroughly with a towel. Look for any leftover particles or lint stuck inside. Use a brush and detergent to clean the valve the same way, then dry it off.

After oiling the valve, twist it while you insert it into the casing. That will distribute the oil evenly. Also, make sure the alignment tab clicks into the groove correctly. Sometimes, I'll also put a little valve oil in from the bottom, before installing the spring and bottom cap. Again, that is to ensure the oil is evenly distributed.

As you reinstall the valve, you'll be able to feel a little resistance as you twist the valve into the casing. If you feel the valve is still binding a lot on any side, there is a possibility is that the valve is bent or the casing had been dented.

In that case, you're probably screwed. I have been able to make one slightly dented casing work. That was by manually pushing the valve up-and-down repeatedly until it sheared off bits of the offending casing.

Regarding stuck slides:

Loop a towel through the bend of the slide. (If a towel won't fit, use a short rope.) Ask a friend to hold the trumpet steady. Then jerk the towel hard a few times. I've found that sharp jerks (as opposed to a steady, strong pull) gets the slides unstuck quicker and does less damage to the bracing.

Once the slide is out, clean it with a brush and detergent, then dry. I lube my slides with plumber's Silicone Grease. It is available in the plumbing department at Lowe's or Home Depot for about $2. That grease has exactly the right consistency and doesn't degrade over time.

One final touch is to use a snake (a specialized trumpet cleaning brush) to scrub the bore of the entire trumpet. Again, flush hot water and mild detergent through as you snake it. You'll be surprised at the junk you find in old horns. It will smell and play better after you finish !

Hope this info helps !

I'm sorry. I can't tell you how much it would be because I don't know. My sister passed out and fell on her trumpet (boy that was fun). Our school's band director's nephew (I think) goes to U of I and is majoring in stuff like that, so he fixed it for us. Now there's still a semi-large dent, but it doesn't affect playing it. Maybe you could try finding someone who knows someone else to fix it for you for free or cheaper than what it would be?