I cannot remember how much it costs as it was about seven years ago we had our JRT bitch done. I think it may vary with the size of the dog, but not sure. I am sure if you give your vet a call they will be able to advise you or someone on this forum will probably have more of a clue than me!
It is strongly advised because it prevents certain cancer (can't remember what it's called, possibly breast cancer). It also prevents pyrometria (i think that is what it is called) which spayed dogs cannot get, as well as phantom pregnancies. It also means if your bitch gets in with any entire males there are no chance of pregnancy and it stops heats, which can be frustrating because of the change in behaviour and it can be messy.
I would definatly have any dog done, be it male or female if i had no intention of breeding it.
You will find reasons for and against getting her done. It reduces the risk of cancer and so I wanted to get my girl spayed. Also the rescue centre only let us adopt her on the condition she had the op when she was old enough. She bounced back very quickly and now I'm glad it's done and out of the way.
I don't know how much it normally costs, but our local vets recently ran a 'special offer' for a few months and it was well below £100. In contrast to that, we've recently spent almost £400 on vet bills because our dog developed pyometra, which could have been prevented if she had been 'done'...
We got tinkerdog done as it was less hassle, as she roams free and had to be closed up when in season, and we were getting a second, male dog.
It was around £80 and shes a med. sized terrier.
I think around here charge about £120 but depends on the size of the bitch
imo i wont spay at the earliest after their first season as some bitchs start to have season well over a year ...my bitch had her first S at the age of 15mths
i have two un- spayed bitches ages from 7 and 3 years, have had no problems
cant understand why vets recommend to spay before 6mths as bitchs need to mature..but this my opinon