Chills,
A one gallon plant generally is about $12 (give or take depending on distance, and the rising price of gas), mostly because it costs a certain amount to deliver a package to a given address. Adding the weight of a second plant, usually adds only $2-3, as the cost of driving to the address has already been covered, and only extra weight and space needs to be paid for.
Also, because I am a small, small business, UPS is more expensive for me than if I shipped a 100 packages a day. I can't change that.
I can ship any time, but avoid doing so when weather is freezing, or hot. It also depends on distance. One day in transit to a location in CA is different risk than a week to CT. I have several plants set aside, waiting for weather to be a little warmer, before shipping.
I try and charge as close to actual cost as is practical. Long story, short, it is a business, but I still understand being a customer, and enjoying a reasonable price. I really try to put myself in the customers shoes, and treat them like I woud expect to be treated. I'm not making a living at this, but covering costs (water, fertilizer, pots, the website, this forum, etc.) and having enough left over to acquire new varieties. I have spent a lot of time collecting different varieties, often with the generous help of people on this forum, with the goal of making them more widely available to the entire fig community. Making them available takes time and money, but it is closer to a "labor of love" than it is to a "get rich quick scheme". I spent almost 30 hours taking and preparing cuttings, and many hours packing and shipping orders. I spend many hours a month entertaining visitors and customers, demonstrating many aspects of growing figs, and seeking to match people and their climates with suitable fig varieties. It is a lot of fun, and I enjoy it very much, but it also takes time.
That's probably more than you wanted to know.