I had 8 diecast cars listed for my first group of Ebay auctions. 7 sold today. All were listed for $9.99 with $10 shipping. The highest bid was $15 but most sold for the listed price. I hate to see all that money wasted on shipping. I bought the cars for between $10 and $22 so I did lose a bit.
My biggest mistake this time was that I forgot that I had a business account with Paypal and it charged me $1+ for each payment! That's $7 off of my profit plus Ebay fees! That's horrible. I returned my business license last month since I am out of the short-term rental business. I only had a business account so that I could accept credit cards but everyone paid their rent by check. I should have fixed my account. Too late now.
In order to save a little money on shipping I am weighting a box vs. a pre-paid box. Depending on the zip code, it can be cheaper to ship with my own box. Plus there is a slight discount for buying postage online. If I save 70 cents on shipping it will off-set the $1 Paypal fee a little.
Next time, if there is a next time, my account will be fixed. I had to send a message to Paypal customer service to get help with changing my account. I think I might list the cars with buy-it-now prices that are a little closer to my actual cost. That way if they don't sell I won't be disappointed and if they do sell I won't lose so much money.