Sewport might be a bit more popular than MFG. We know about 2 links to it since March 2021 and only 2 links to MFG. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Honestly, I'm not sure about prototyping capability on upwork. I guess a few of the freelancers there would have some capability of making prototypes -- especially if 3D plastic printing would work. Anyway, once you have a design you can put it up at mfg.com and get quotes to prototype it. Source: about 1 year ago
One way to go about it is create a Request For Quote, provide an outline and a set of deliverables and ask for quotes on a site like mfg.com. Source: almost 2 years ago
Vist sewport.com, or sourcingplayground, they are platforms to connect buyer and supplier. There are low MOQ manufacturers there (as low as 10 pieces per design), suppliers will contact you with their quotes, ask them to provide streetwear portfolio, then you'll be alright :). Source: over 2 years ago
In addition to Etsy, Sewport (https://sewport.com/) might be a good option. You submit a project idea and get proposals from people that can fulfill it. Source: over 2 years ago
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