What watch is this and how much is it worth? KC1558 A126-10

The value of a Pulsar watch can vary depending on several factors, such as its condition, age, and model. The Pulsar 160622 watch is a vintage watch and the value of it would depend on the condition of the watch. A watch in excellent condition with all of its original parts and paperwork would be worth more than one that is damaged or has been modified.
It's also worth noting that Pulsar watches were first produced in the 1970s, so the age of the watch is also a factor in determining its value. Watches that are older and in good condition can be considered collectible and therefore be worth more.
It's difficult to give you a specific value without seeing the watch and knowing its condition, but I suggest checking with a reputable watch dealer or watch appraiser for an accurate value. Also, you could check online marketplaces like Ebay, Amazon, or Chrono24.com to see prices of similar watches being sold, but keep in mind that prices can vary depending on the condition and location.

Depends on condition, age and any accessories

Will cost more to change the movement than its worth.....lose it.

If you are interested to have some idea about how much are worth your unspecifies watches, go to ebay and look for similar models. might give you idea if worth or not to repair them
Please take note that an old watch, if not in good shape, faultless, has really no collectors value, just because it's old. There are too many old watches around. If has gold parts, only worth value of the gold. Goldfilled watches are not worth anything if they are not perfect.

That model does not come with diamonds therefore the diamonds are what's known as aftermarket. I can also tell from the photo that they are aftermarket because they did an awful job setting them in the watch. That watch in its original unaltered state is worth $200. With the aftermarket diamonds though I would say that your watch is worth between $75-$100. Believe it or not the addition of aftermarket parts even diamonds takes away from the value of a watch.

If it's a men's watch it is still worth around $100 - $120 depending of which model, so it's still worth changing the battery my friend.
Marcelo

This is a scam. Don't do it. J.

A quick look at ebay shows plenty of Bulova watches and only a few looking for a worthwhile price.

I think if you have it repaired for sale it probably won't be worth the effort or expense. If the watch has sentimental or nostalgia value to you I think that is what would make it worth getting a good watchmaker to look at it.