Hmm.. Here's a link to Adobe page for Photoshop CC (which is their latest version and monthly installment version):
creative.adobe.com/plans?singl…Looks like they offer Photoshop + Lightroom for $10 too. I don't know the requirements of if your computer will be compatible with Adobe Cloud or not so you'll have to check and make sure!
Getting Sai is a little tricky and I honestly don't remember how I got it. But ClipStudio is very similar to Sai. It's like Sai + photoshop combined. So I don't think you need Sai if you're going to get clipstudio.