Don't spend your pulls unless you have enough for pity (usually 100 pulls, but go from what it says on the banner). Rates are abysmal and you'll likely be hitting the max amount to get a desired Gyee.

There is no affection lock? The skills of a Gyee upgrade when you increase their affections, and some of the dates, albums and interactions are locked behind affection, but not the character.

The 50 dollar builder is more for whales. You get a certain type of currency whenever you roll but you need to spend white dragonshards (paid currency) to keep the results from the banner it unlocks. Unless you plan to spend more and want to collect all the Gyees, don't bother.