Measure before you compare quotes
A "2-car garage" ranges from about 400 to 600 square feet depending on the build, which is a $1,600 swing at the same rate. Measure the actual slab, length by width, minus any step-downs, before assuming a quote is high or low relative to what a neighbour paid.
What pushes a 2-car garage above $6,000
Removing a failed hardware-store coating adds $1-$3 per square foot. A high moisture reading requiring a mitigation primer adds $2-$4. Heavy salt scaling near the door needs rebuilding rather than coating over. Choosing metallic instead of flake moves the rate to $12-$18. Any two of those together comfortably exceed $6,000.
What brings it under $4,000
A clean, sound, uncoated slab with no cracking and a normal moisture reading, finished in a solid colour rather than flake, is the cheapest legitimate build. It is worth understanding that solid colour shows every speck of dust and loses slip resistance as the topcoat wears. The saving is real but so is the trade-off.
Comparing against a DIY kit
A consumer kit for the same garage is $200-$600, which looks like it settles the argument. Those kits are 40-50% solids water-based epoxy over acid etch, producing roughly a tenth the film thickness on a surface that was never mechanically opened. Most lift under hot tires within two seasons, and grinding off the failure costs more than the original professional quote.
Want this answered for your slab?
Free site visit with a moisture reading, then a written fixed price. Across the BC Interior.