The item slots in Wild Rift are different from League of Legends; there are 5 item slots and 1 dedicated boots slot. In other words, you absolutely have to buy boots for a full build.
So, how gold-efficient are these boots?
All upgraded boots cost 900 gold, with the 400-gold basic Boots of Speed as the only component. Before we look at the efficiency of the boots, let's check out the basic items for comparison.
Basic Boots, 400g, +25 Move Speed
Ruby Crystal, 500g, +150 HP
Mantle, 500g, +20 Magic Resist
This one doesn't even exist in Wild Rift
So, what about the boots?
Mercury's Treads
900 Gold
+200 HP
+20 Magic Resist
+50% Health Regen
+45 Move Speed
As you can see, they give you stats worth way more than the cost, even excluding the movement speed. Because of this insane performance, unless it's a special case (extremely mana hungry, wanting to stack Heartsteel ASAP, saving up for a full Legendary item from the first back, or backing without even 900 gold), the goal is to buy them on your first back. Some people even start with basic boots just to get them faster. (Since there are no potions in Wild Rift, you're starting with 400 gold while others bring 500 gold items.) I'll be back next time with support-exclusive items.