Hi there welcome to PTalk.com!
AD charges a flat rate on shipping at 19.95 when shipping unless you order over 200 dollars worth of products.
At 19 years old, be weary when using products like TUTH. Use them sparingly. Instead of TUTH, you might want to use Ammo instead. Also, A314 might be too overpowering at your age for now, instead you might want to go for IG.
Theres no exact rule on which products which you need to get, but these are just guidelines 
You can read up on them over here:
https://pheromonetalk.com/t/an-introduction-to-mones-names-size-strength-use-effects-length-of/43003
Cheers!