I like Ableton's operator, and simpler has a simple, but I think powerfull lfo and filter section for creating wobbly basslines for dubstep. Just load in a warm bass sample, filter and resonance for thick, warm and fat sound, out the lfo on note sync (I like 3/16) turn it up et voila!
Good tip to to make your bass more in depth, is to use the same sample and notes but make 3 channels with 3 different filter settings, like verry filtered, medium filtered, almost not filtered = subbass+audible raw buth warm and wide bass + sharp uncut high = tha shizzle!!!
Also turn the sync on the lfo for the sub to 1/4 or even less, otherwise it's just painfull and the deep understream will be absent
And if you want full ableton for less money buy an controller or instrument whatever that includes a Lite version of live and a SERIAL!!!! with that serial you can have an upgrade to full versions for like 180 euries (dunno if it's a promotion or policy)