Flat fee or hourly, what the government charges separately, and the questions that turn a vague immigration quote into a number you can plan around.

Two quotes are only comparable once you know which stages of the case each one covers. Ask every office to mark exactly where its work stops.
A flat fee prices the case rather than the hours, which suits predictable filings like renewals and naturalization. In exchange, the written scope is usually drawn narrowly.
An hourly quote should state the rate for each person who may work on the file, an estimated range of hours, and the minimum billing increment. Six-minute and fifteen-minute increments are both common.
A request for evidence is a routine part of many cases and can require substantial drafting. Confirm in writing whether responding to one is inside the fee or billed separately.
Two attorneys can quote the same family petition and land thousands of dollars apart without either one being dishonest. The gap is usually scope. One number covers preparing and filing the petition and nothing else; the other covers the petition, the follow-on adjustment or consular stage, the response to any request for evidence, and the interview preparation. Until you know which stages sit inside the figure, the numbers are not comparable. The useful move is not to ask who is cheaper, but to ask each office to mark where their work stops and what happens next.
A flat fee prices the case, not the hours, which is why it suits work with predictable steps: a marriage-based petition, a green card renewal, a naturalization application. The risk shifts to the attorney, and in exchange the office writes the scope narrowly. Hourly billing is common where the shape of the case is genuinely unknown, in removal proceedings, waivers, or anything with a prior denial or a criminal record attached. The honest version of an hourly quote includes an estimated range, the rate for each person who might touch the file, and the minimum billing increment, often six or fifteen minutes.
Neither model is superior. What matters is whether the agreement says what triggers a new charge. Ask directly: if the government issues a request for evidence, is drafting the response inside the flat fee or is it a separate engagement with its own price? If the case is denied, is an appeal or a refiling covered? If the interview is rescheduled twice, does the office bill for each preparation session? A firm that answers those in specific dollars has thought about them before, which is itself information.
Filing fees go to U.S. Citizenship and Immigration Services, or to the Department of State at the consular stage, and they are set by the agency rather than by the office representing you. A quote that folds them into one lump sum is not necessarily hiding anything, but it makes the legal fee harder to see. Ask for the two figures separately, and ask which form numbers are being filed, because the fee follows the form. Fees change by regulation, so a quote written months earlier may cite an outdated amount. These payments are non-refundable once filed, whatever happens to the case.
A family case usually carries third-party expenses that no attorney controls and many quotes omit. Foreign-language documents, birth records, marriage certificates, divorce decrees, police clearances, need certified English translations, priced per page. The immigration medical exam is performed by a civil surgeon or panel physician of the government's choosing, paid directly to that office, and vaccinations can add to it. Then the small items: passport photographs, certified mail or courier, obtaining sealed copies of vital records from a state office, and sometimes travel to a consulate in another country. None of these are large alone. Together they are not trivial.
Read the engagement letter as the actual product. It should name the specific matter, list the stages covered, state the fee and the payment schedule, identify who at the office does the work, and explain what happens if you stop the representation or the attorney withdraws. Flat fees are often collected in installments tied to milestones: a portion on signing, a portion on filing, the balance before the interview. Hourly work usually requires an advance held in a client trust account and billed against, with statements showing the drawdown. Ask whether unearned money is refundable and how quickly it is returned. The Federal Trade Commission oversees deceptive practices in consumer services, and immigration services advertising in particular has drawn attention, so a written scope is protection as much as paperwork.
Five questions do most of the work. Which forms are you filing, and what is the current government fee for each? Where does your representation end, and what is the price of the next stage? Is a response to a request for evidence included? Who prepares the documents, and what is that person's rate if the billing is hourly? What outside costs should be budgeted, translations, the medical, the records, and roughly what have those run for similar cases? Ask the same five of every office you call, write the answers down, and the quotes stop being numbers and start being descriptions of work.
The quote worth accepting is rarely the smallest. It is the one you can restate accurately to someone else: this much to the attorney, this much to the government, this much for translations and the exam, paid at these three moments, covering these stages.
Filing fees are set by the government and go to the agency, not the attorney. Ask for the legal fee and the government fee as two distinct figures.