A mobile notarization quote can contain two different kinds of charges: the fee for the official notarial act and a separate charge for travel or other agreed services. Ask for both parts in writing before confirming an appointment.
The notarial act has a legal fee limit
Texas Government Code §406.024 sets maximum fees for specific notarial acts. The amount depends on the act and the number of signers or signatures; it is not one universal price for every document. A notary may charge less or nothing. The Texas Secretary of State publishes the current fee schedule and explains that excessive notarial fees can lead to discipline.
Travel changes the total
A provider may quote travel based on the destination, requested time, urgency, and access requirements. Ask whether a return visit, parking, printing, witnesses, or a cancellation would add a charge. The official notarial fee and any other charges should be separately described before you agree to the total. A website estimate is a planning tool, not a confirmed booking or final invoice.
What to send for a useful estimate
Give the service area or ZIP code, preferred date and time, number of people who will sign, and the general document type. Keep legal, medical, ID, and payment details out of the web form. If you are unsure which notarial act a document requires, ask the person or organization that prepared or will receive it; a notary cannot choose it for you.
Source: Texas Secretary of State. General information only; an attorney can advise on your document.