Guild Wars 2

Basically the title, just curious about buying it, but atm I don’t have the money to buy the 79.99 one, but if I buy the base 29.99 one to get the 80 boost, can I then upgrade to the other one later on?

Q: If I purchased the Standard Edition of Path of Fire, can I upgrade to Deluxe or Ultimate?

A: You can purchase a digital Deluxe Edition upgrade through the Black Lion Trading Company in-game store. The Ultimate Edition of Path of Fire must be purchased as a complete edition, and the Standard and Deluxe Editions can’t be upgraded to Ultimate.

https://help.guildwars2.com/hc/en-us/articles/115010688287-Guild-Wars-2-Path-of-Fire-FAQ

you can upgrade to the deluxe one for gems not the ultimate one.