MaximDL sure is expensive when comparing it to freeware!
Alas, I wouldn't buy it if all you want to use it for is guiding. MaximDL is uber feature rich on so many levels from data collection through to advanced processing.
I do get a laugh from time to time on software cost related discussions. We have no qualms in dropping several $1,000 on hardware such as mounts, OTA's, cameras etc. Yet when it comes to software, spend is insignificant in comparison. Make no mistakes, without software your telescope is nothing but a clump of metal, glass and electronics. Don't be shy on spending if its going to improve your output.