To post pictures you need to upload them to a site like photobucket.com, you can do that with a free account, then post the link to the photo here.
You can sell transformers here, or any number of online selling sights. But things will probably sell fastest on ebay, unless someone here sends you an offer right away.
A few things about selling on ebay.
1 selling something "buy now" usually gets you a higher price than an auction. But it can take a long time for some things to sell. It could sell in an hour or it might not sell in 9 months.
2 Ebay things sell for a higher price, but don't forget the fees involved. It costs a certain amount to list an item, and then when it sells they charge you 11% of all the money received, selling price + shipping. And paypal will take their cut to. But I think thats like 3%.
3 Always get tracking on anything you ship. If you don't paypal will NOT protect you if the buyer says they didn't get the package. If its like $200 you also need signature confirmation.
4 you have to ship to the address listed in the PAYPAL transaction.
5 Take lots of photos, in all modes if you can. If selling on ebay make sure the first photos shows EVERYTHING. THe box, and all the pieces. Show closeups of the small parts that are usually missing.
6 Use a good title. You want to make sure you use all keywords people search for. "transformers, G1, box, complete, instructions, vintage, jetfire, starscream, etc...."
7 be thorough in your description. if they is loose joints, cracks, missing parts, paint wear, scratches, yellowing, markings, rust. Make sure you list that in the description.
8 if you are a new ebayer they are going to hold on to your payment for like 2 weeks or a month to make sure that there isn't a problem with the transaction.
For a complete jetfire with box in good condition I'd ask $200 + shipping. Include signature confirmation, insurance, supplies like bubblewrap, and ebay's fee on shipping charges in the shipping total.
Starscream is harder to price. I'd say probably between $90 - $125 + shipping.
Of course condition will determine the price