What DIY really costs
Doing your own US prep looks cheaper until you price the whole thing: a US receiving address, someone to open and inspect cartons, label to FNSKU spec, build compliant shipments, manage returns, and stay on top of Amazon's changing rules. The prep fee you avoid is small next to the cost of one rejected shipment, one aged-inventory surcharge, or one account-health hit from a labeling error. DIY hides its cost in your time and in mistakes.
Where DIY breaks down for overseas sellers
If you are based in India, DIY also means being the importer of record from another country, clearing customs yourself, and handling US sales tax and IRS filings without a US presence. Each of those is a place a first-time seller loses weeks or makes an expensive error. Think14 absorbs all of it into one flat-priced service from an owned Austin facility, so your only job is sourcing and selling.
When DIY still makes sense
DIY genuinely fits sellers who already have a US operator or warehouse, low volume they can hand-prep, and the time to learn the rules. Past that point, a 0.75 dollars per unit prep with a 48-hour SLA and no minimums usually costs less in total than the hours, errors and surcharges of doing it yourself, and it frees you to spend time on the parts of the business that actually grow it.