First trial order of soy candles for boutique retail — samples then 600 pcs

We currently buy our candles through a domestic wholesaler and want to try sourcing directly for better margins, starting with a small trial order before we commit to anything larger. We're looking for soy wax candles in glass jars, roughly the 130-150g size, in 2-3 scents that would suit a home and lifestyle boutique — nothing too niche. A simple label is fine, it doesn't need to be elaborate for this first run. Could you send samples first so we can check quality and scent throw in person? Once we're happy we'd place an order of around 600 pieces to test in our stores, small enough that we're not stuck with dead stock if it doesn't sell. We haven't sourced internationally before, so we'd appreciate a straightforward explanation of what's included in your price (packaging, documentation) and what we need to arrange ourselves for import. We'll need whatever compliance paperwork is standard for candles sold at retail in the US. Please let us know: sample cost and whether it's credited back on the order, pricing at 600 pieces, minimum order for a reorder, and how shipping and customs typically work for a first-time buyer our size.