What exactly are you looking to test? Usually product testing is to see if something works without breaking. But clothes are clothes. They may fall apart eventually with wear but you won't know that for a long time (though you obviously know they hold up using them yourself). When we started our business, we just launched it and went right into sales, but we used our products ourselves before and gave a few to friends to use. We got photos from these that we could use to promote ourselves on our website, Facebook, for ebay and other sites, and we got a few reviews from friends to start us off. I personally would do that. You could even ask any friends who do photography as a hobby to take some photos for you in exchange for some clothes. We did this with a friend who did a photo shoot for us and we got some amazing photos from it that we still use like 4 years later.
You obviously have a baby and toddler about the right ages and you probably have friends who do as well. I would ask for their help in modelling a few and maybe giving them an outfit to review for you. And then I would just go for it. Put things up on etsy or your own website and offer to give like 5% off if people agree to instagram or review it or provide some sort of positive feedback. I think most people are happy to do that. I think 'product testing' makes it sound more involved than it is and may put some people off. But usually if you explain your business is new and you'd like to get some photos and reviews, most people are happy to help if the products you are providing are quality and they're happy with them. But if you are serious about it, I'd start off looking to make money rather than selling things at cost. You'd be amazed how actually people will shift their option of your product if they buy it for cheap and your reviews won't be as good. If you sell it proper retail value, people do actually think differently about it and will give you better reviews. It's just the psychology of it.
Good luck! We started our business when our daughter was 4 months old (my husband does it full-time, though I help out here and there and do weekends when it's busy, I have my own career and full-time job apart from that as well by choice). It's made an incredible difference in our quality of life and means that we get to spend a lot more time together now that he has so much more flexibility.
