For hoodies and knits, order by the flat measurements on the size chart, not the letter, because "oversized" cuts and fitted cuts of the same size can differ by several centimetres in the chest. With no service fee on Oopbuy, the value question is simply getting a piece whose fit and fabric weight match what you pictured.
Fabric weight is the personality of a hoodie. A heavyweight fleece (higher gsm) sits structured and holds its shape; a lightweight one drapes soft and packs down. The listing does not always state gsm, so use the QC photos and the seller's own description, and if you want a specific feel, ask before ordering. For knit sweaters, gauge matters just as much: a tight, fine gauge looks cleaner but shows pulls, while a chunky knit hides them but runs warmer and bulkier.
Measure against a garment you already love. Lay it flat and record pit-to-pit, body length from the high shoulder point, and sleeve length. Compare those to the chart. Two habits save most returns here:
Print and embroidery are the QC focus for graphic pieces. In your photos, confirm:
Also glance at construction details that budget makes skip: a lined hood, a flat-locked or double-needle seam, and a functional drawcord with intact aglets. These are cheap to get wrong and easy to spot in photos.
Knitwear and fleece compress well, so they consolidate nicely into a shared Oopbuy parcel without dominating the freight. For live shipping estimates, pricing, and any current offers, check the Oopbuy listing and your dashboard rather than assuming older figures. A little upfront measuring turns a sweater order into a reliable staple instead of a gamble.