Look at the one from Vela, slightly less painful to the wallet:
https://www.velasailingsupply.com/boomkicker-for-sailboats-16-to-19-k0400/Advantages: The boom sits in a sling, so you don't have to take anything apart when you're unrigging the mast; the kicker attaches to the mast via a slug in the mast slot, so no drilling. Disadvantage - one more thing going into a very tight space (thus applies to any kicker, not just Vela's).
I had considered a kicker and decided against it, both for cost/benefit and space considerations. In the end, I've rigged a topping lift with a "twist." Instead of leading the topping line from the end of the boom to the mast head, thru a block then down to the foot of the mast, I go the other way. I have a light line permanently attached to the top of the mast (right below the windex, above the main halyard block), then it goes to a cheek block at the end of the boom and forward to a small cleat at mid-boom. The cheek block has an open back, so I can simply pop the topping lift off it when unrigging the mast. Advantages - topping lift always ready, and easily adjustable from my usual sitting position - I slack it off when sailing in most airs so it doesn't catch on the leech, and I tighten it up in light air or running DDW. I tighten it quite a bit when I take the sail down, just to raise the boom out of my way. Disadvantage is that I do have to remember to adjust it 2-3 times during my sailing session (setting out, then when dropping sail), and if I don't slack off enough then the lift gets caught on the sail. Also, the mid boom cleat is hard to access when the sail is furled over it. And more screw holes in the boom (NOTE). Still, the good outweighs the annoyances, at least for me.
Tom
NOTE: You may want to include the price of a tap set and center-punch ($35-45 total?) in your cost analysis. I'm assuming you already have a drill and bits. I bought the taps and punch specifically for my running rigging work, but have since used them for other household projects.