Normally, there is no charge to fix a few keys that are not working.  Most of the time this only requires fixing an obstruction, making an adjustment, regluing a part, or removing a foreign object (coin, hair pin, dead mouse, etc).  Whenever the repairs require more than a few minutes, I will give you a quote for your approval before proceeding.  Many times this is a nominal charge of $15-$30.  Sometimes, I'll need to take the action to my shop.  Almost always, the cost is not as much as you expected, and usually less than my competition

Pianos in really bad shape may need some of the work done listed in this table, but usually you can get by by fixing just the missing/broken parts without replacing the whole set.