I have seen some of the more 'exotic' tomato seeds running as much as $6.50 for ten seeds...$4 - 4.50 per pack isn't that unusual any more.
The first site page of Burpee’s tomatoes look to average $6. Then you get to add on the shipping cost. All the more reason to save the seeds of whatever you’re growing.
Anyone who doesn’t know, tomato seeds need to sit in a glass of water for a few days until there’s a scum on the water. Rinse them in a strainer. Lay them out to dry and then store for next year.