I've never used a consignment shop. I've purchased from a consignment shop but not used.
If I was looking for fast money - I did Craiglslist and listed a "lot". if I was looking for serious money - more than $25 for them - I used ebay. I still use ebay and craigslist to unload my unused/unwanted items.
On ebay - your first 100 listings are "free" but you have to pay a 9% final value fee. which sucks. ebay you can sell world wide - although NOT to Italy - they have clothing restrictions....BUYER pays shipping.
On Craigslist - it's free - no fees, no hassles - really. Craigslist is local. I would suggest you meet in a mall or parking lot.
Either Craigslist or ebay requires GOOD to GREAT pictures in order to get people to look. The title line is VERY important - for example
LOT infant girls clothes 3-6 months GAP outfits sets
A "LOT" signifies you have at least five items in the listing.
It helps if you have "name brand" items. If you have maternity clothes:
LOT Maternity clothes 10-12 Pea in Pod
The benefits of a consignment shop is all you have to do is drop them off. depends on the level of effort you want to extend