Prices do fluctuate and normally go up for the weekends.
What we do is decide the hotels we want to stay in and then check the prices out.
When the prices match something we are prepared to pay we book, however we may not reach that point and so go without or find an alternative.
I mention multiple hotels because we were once looking at East Cuba where there are about 8 hotels in a stones throw. We narrowed the choice down to hotels we wanted to go to and then those we could afford. I kept an eye on the prices and strangely one of the ones we could not afford dropped a couple of hundred and came down to within £25 of the hotel I was watching which did not drop much at all.
We went the extra £25 and had a fantastic time.
Be warned though that there was a bug on the website if you clicked on the sit together option while checking prices. Any change to accomodation or party make up was totally ignored if you clicked back on the option and you were returned to your original holiday and pricing. I did report it but it had still not been fixed the last time I used the site.
I couldn't get a decent price I was prepared to pay in 2007 and so ended up phoning an alternative TO who provided us with a better holiday at a much better price. No use to you though as they specialise much further west.