Two agencies quote the same monthly figure. One of them is doing four times the work. Nothing in either proposal makes that obvious, because the two documents describe the same activities in the same language.
These are the questions that separate them.
1. How many pages a month, and does a page mean new or edited?
Published ecommerce packages at similar prices vary enormously in output. At the entry level you will find one provider delivering around twenty optimised pages a month and another delivering four to sixteen, for a difference of a few hundred dollars.
Ask for a number. Then ask whether a page means a new page written or an existing page edited, because those are very different amounts of work and are routinely reported under the same word.
2. What is the initial term, and what does it commit you to?
This is the detail that most changes the real cost.
A widely cited entry tier is 899 dollars a month with a six month initial term. That is not an 899 dollar decision. It is a commitment of roughly 5,400 dollars before the month to month period begins.
A rolling agreement at a slightly higher monthly price is often cheaper in practice, because you can stop after two months if the work is not landing. Compare a six month term against another six month term, never against a rolling one.
3. What sits outside the retainer, and at what rate?
Content production, link building, paid advertising and development time are frequently excluded from a retainer even when the same agency offers them. This is the most common way a quoted number quietly doubles.
Ask for the out of scope hourly rate in writing. One agency publishes theirs at 185 dollars an hour, which is unusual and worth rewarding.
4. Where do the links come from?
Some packages advertise fifty to two hundred links a month inside a tier costing under a thousand dollars. Links at that volume and that price are bought rather than earned.
Google's link spam policy acts on the site receiving the links. If they are devalued or penalised, the consequence lands on your store, not on the agency that sold them. A package delivering one to three earned links a month is doing less, and what it does survives an audit.
The question behind all four
Can you check, at the end of the month, whether you got what you paid for?
If the answer is a countable number of pages, links and hours, you can hold someone to it. If the answer is a description of activities, you cannot, and the price is not really a price. It is a subscription to an effort.