Can you be more specific? How large is large? Do you want to sell it as a single lot through an auction house, or as individual items or small groups on
ebay or HipStamp? What countries?
Yes there are a lot of Internet dealers who will take items on consignment, and usually charge between 20-30% commission. Most of them want items that will retail for $5 or more, so figure minimum CV $25 per stamp or lot. Might be better selling directly to a dealer at a local stamp show. Totally depends on exactly what type of material you are talking about.
In some cases (such as post-1940s addressed FDCs) there is very little interest and the shipping fees are a bunch higher than the material is worth itself so you can't hardly give them away.
Your message title says these are common stamps. If truly kiloware, with hundreds or thousands of the same common stamps, there is a different market for that and those may sell better through a crafting marketplace such as Etsy.