everything costs a price/percentage to sell it on ebay.
The basic starting price to list something (from $1.00-$9.99) is 40 cents plus a percentage of the ending price.
As well the most commonly accepted form of payment on ebay is paypal. They take their fees out as well, even though they are owned by ebay.
To sell on ebay you will need a credit card to register and a bit of common sense but its not to hard.
Ex: don't post something at 2:00 in the afternoon because it will end at 2:00 in the afternoon, and well, there aren't a lot of people home at their computers at that time!
*Oh I also recomend you get a cheap digital "mail" scale (I got mine on ebay for like $10.00.) That way you can weigh the item and then just calculate how much it will cost right online. The buyer is the person who pays for the shipping cost but if you think it only weighs 2 pounds and tell them the cost to ship 2 lbs, they pay that then you find out it really weighs 3lbs then its going to have to come out of your pocket. This way you won't have to take it to the post office to see how much it weighs.
I sell on ebay and how much you make depends on what you sell.
Sometimes things go for cheap, and sometimes you get something good out if it.
My best suggestion is save the box!! anything you want to resell sells better with the box.
Ex: I sold my sons car seat, with box and manual for $10.00 more then I paid for it, go figure.
Ebay is a great way to make extra money, I have sold almost ALL my sons old things on ebay as he outgrows them.
However if you are only planning on selling off your old childrens stuff you may not get $400.00 a month. But some money is better then none, right?
Really how much you make is dependant on how many items you have up there to sell. 40 items selling for $10.00 each for example will make you 400 in the month, but if you only have 100 baby items then how long will that last you??
You could space it out and make less a month and the items will last longer but again its an issue.
What I have found that works is to find something other then just baby stuff to resell.
There are a lot of people who join mary kay or get products like baby slings in bulk and resell them on ebay instead of to people they meet. Some people resell old videos from librarys or video stores during their sales when they are getting rid of old stock.
Others make stuff like candles or soap. There are a lot of options to look into.
But I will also tell you ebay does take some work. Its not just click and go. It takes some time to put them up on ebay as each item you have to take its photo (most items without photos don't sell) and fill out the information about it. And when its done you have to ship it. The more time/items you have the more you will make.
*addition: You do not have to ship the item out until it is totally paid for (ie: you have the money/the checked cleared, ect. not just them telling you that they sent payment.)
It is free to sign up with paypal (which most people use) but they take their fees. You can set paypal up right to your bank account and can move your money straight into your account if you want.
Another thing I sugget to protect yourself is to put delivery confirmation on EVERYTHING you ship. It costs 45 cents more, include it in the shipping price you charge the buyer, it gives you a tracking number through the post office. If the person tries to scam you and claims they never got the item, ebay will make you refund them the money, they automatically will withdraw the money from your account, you are out of luck!
If you have a delivery confirmation number though they can see it was shipped and you won't be scammed (I've had this happen) Ebay doesn't really care if you have a post office recipit, they just want that tracking number. Also if something happend (like the label on the package falls off) you can find the item and have them put a new label on it, it won't get lost in the post office.
*another addition* Also try and save money on shipping items buy reuseing shipping materials. Get boxes at target when they are stocking the shelves and wrap them in a brown paper bag instead of paying $5.00 to buy a box. If you get things in the mail in padded envelops cut them open nicely and then they can be taped closed with packaging tape. Get gifts wrapped in tissue paper? save it to wrap around things you sell that might need a bit of padding.