There's no need to waste money on professional sensor cleaning - provided you follow basic procedures that have been covered here and elsewhere a number of times - just be careful and use the correct kit...
I clean the sensor once a month or at any time if I'm forced to change lenses outdoors...I use Eclipse swabs and cleaning solution.
For the exterior, a damp flannel facecloth and a toothbrush gets rid of stubborn grime ingrained in the textured rubber covering - a 2" paintbrush does the rest of the outside.
If the camera gets particularly dirty (dirt combined with sweat goes like cement and is particularly horrible to get off) then I use the toothbrush with warm water...the dry paintbrush is then used to 'tease' excess water out from around the various buttons controls and dials...
Finally a can of compressed air is used to dry around the controls - but never the camera's interior.
For the mirror and interior, I use a rocket blower - any debris on the mirror that fails to budge is gently teased off with a dry sensor swab.
Sometimes dust finds its way behind the eyepiece and when this happens I remove the outer eyepiece by first operating the eyepeice blind, then gently wipe the dust away with a faux chamois from Calumet...I never use the rocket blower here because it just pushes dust all over the pentaprism and is impossible to get at.