What you pay each time someone clicks your ad. CPC is where the cost of traffic becomes visible, but it is a means, not a goal: a cheap click that does not convert is expensive, and a dear click on high-intent search can be the best money you spend. On Google, your feed and ad quality directly determine what you pay - a great Shopping feed with a mediocre bidding strategy beats the reverse. The mistake is optimising for cheap clicks instead of profitable customers; judge the click price against what the visitor is worth, not against zero.
Benchmark. Google ecommerce CPCs average around $1.16. Shopping runs roughly 43% cheaper than Search ($0.50-2.00 typical), which is why it is the efficient core of a DTC account; non-brand generic terms cost $2-6, up to $8+. Rising CPC with flat CTR points to creative fatigue.