Okay, first question I'd have is what is your budget?

If you have zero funds available for a program I'd say try working with GIMP (http://www.gimp.org) for a while and see if it works for you. By all accounts it's a powerful program but it has the downside of being built by neckbeards for neckbeards. (I.e. the user interface is best described as clunky.)

If you've got funds Pixemator (http://www.pixelmator.com/mac/) is a graphics program that is highly rated, has a lot of features, and is relatively cheap ($29.99 USD on the mac app store). I don't know if it can connect to your tablet but if anything has a good shot short of a full fledged adobe product that'd be it. In fact the Pixelmator company has specifically been targeting the niche of folks who want to have a powerful graphics program to play with but aren't big enough users to rate the need for a full on Photoshop suite.

Beyond that of course there's always the big brother of the graphics world, Photoshop. It's expensive, requires a monthly subscription now, but it's powerful and is the go-to application for most chores. Unfortunately I don't have access to a free license key, however if you've got a .edu E-mail you might want to look at their student pricing. (http://www.adobe.com/creativecloud/buy/students.html?sdid=KKTJB&skwcid=AL!3085!3!56599028062!e!!g!!photoshop%20student%20pricing&ef_id=U4-wEQAABEh4iHTk:20141223202005:s)

Sorry I can't be of more help!

--Ebondragon

Well the thing is, I mean an art drawing tablet I hope to get sometime. No clue what a good one would run. As for $30, that might be within range. Right now though, I am focusing on the computer. Get that first, then set it up then I can figure everything ELSE out. Till then, I am using a damn near 16 year old mac g3 233mhz for scanning. Zip drive for transfer. >.> Talk about dinosaur tech here...

Heh that is ancient. Still I can understand your priority there saving for new hardware. It's not cheap!

I hope the suggestions that I had were helpful. Sorry I can't do any more for you.

Hit up https://www.firealpaca.com for a free vector graphics program quite similar to SAI.

Krita is pretty amazing for open-source and works on Linux, Windows and OS X. No charge!