Hi Bebb,
Welcome to Affinity Forums :)
If you export your files as PDF's you should be able to open them in Affinity apps without issues. There's no Drawplus native file support.
The price will be the same as the Mac versions.
and to continue on MEB's comments, Affinity tends to be cheaper than Serif's (Check PC World for example): however there is a trade off. AD runs a lot faster and smoother than DP, but DP has more features. So try both, save your works as DPP/PDF/PNG in DP and open up the latter two in AD/APh and see how things turn out...You'll be pleasantly surprised.
I have old DPP and PPP files, that I have on Win7/Bootcamp, these can then be exported as PDFs from Windows to Mac OS to be edited: RESULT! B)
