A Harbor Freight heat gun is maybe $9... works great on heat shrink.
I do prefer the higher-quality heat shrink from a local electronics parts supply firm. They also have the glue-lined stuff for things I want to seal.
Those Scotch-Lok quick connectors that came with the grip heaters are an absolute abomination. They don't belong anywhere near a motor vehicle, unless it's on the back of a garbage truck.
However, Posi-Locks and Posi-Taps have been proven to work very well on motorcycles. They're a little bulky sometimes, but they're a great alternative for the soldering-averse.
2002 Suzuki DL1000 V-Strom, Dark Metallic Space Blue
1983 Suzuki GS850G, Cosmic Blue
2005 KLR685, Aztec Red - Turd II.2, the ReReTurdening