Get an idea of what individual shipping or shipping through an FFL will cost you. It was more than I anticipated when I recently guessed low at $40. Inflation, I guess.
Make sure to consider excluding some states and US territories. I was once on the hook for mailing an item to Puerto Rico- not inexpensive! Now, I exclude all those non-48 state places like Marshall Islands, Guam, Hawaii, etc.
Know that GB will collect tax.
The extra eyes GB generates that usually equals extra

is worth the GB fees on firearms no longer manufactured/imported and worth north of $1K.