InkScape is open source software, so you don't have to spend to use it. Nice amount of filters and effects.
interface isn't completely intuitive, so you might spend more time getting to know the application. Memory usage should be optimized, as soon you start to add elements InkScape starts to lag. It's not a native OSX app.
If you can handle the trouble of installing it, it might be worth a try.No tags defined