Hello Jorge! Thanks for getting in touch–I’m stoke you’re looking at going PRO and I hope we find a license that’s a good fir for you here. 🙂
One idea might be to get the Business license for the first three sites and a Personal for the fourth. That would definitely save a few bucks if you’re absolutely certain that you won’t need more than four licenses. Note that there is no difference in the level of support or features you get between the different types of licenses–just the number of installs for support and automatic updates.
We do occasionally send out discounts through our email newsletter and on Twitter. I’d definitely suggest plugging in there to stay in the loop for when the next promotion comes around.
Does this help? Please let me know.
Cheers!
Geoff