A first order with any vendor is calibration, not commerce. You are buying information about whether the vendor does what they say, and the product is a side effect.
Read the vendor first
Every Awazon vendor page shows a deal count and a dispute ratio. Read both. A minute here is the most useful minute you will spend. See reading a vendor page.
Keep it small
Smallest quantity, cheapest product that tells you what you need, standard shipping, standard escrow. The right size is an amount you could lose without it mattering.
Let escrow do its job
Do not confirm receipt until the package is in your hands, whatever the vendor says about their reliability. Confirming early is the trap that removes the dispute path you would then need.