A unit rate and a fixed-charge comparison

A fictional workshop has two supplied charging models. Plan A charges three dollars per item and no starting fee. Plan B charges ten dollars before any items plus two dollars per item. A learner says the second plan is always cheaper because two is less than three. Another calculates only the starting charge. A third writes expressions for the same number of items and checks the complete totals. The task asks for the cost of eight items and when the models have equal totals. All charges are hypothetical parameters, not real commercial prices or tax rules. No discount or minimum order is supplied. The explanation should distinguish a per-item rate from a total that also contains a fixed amount, and should compare the same number of items.