Crafting vs buying

So my thorns build I run I use a spear that has crit dmg bonus and extra fire dmg, I bought one for 20-30ex, which may not be a lot but I actually started looking at all the crafting things like essences and realized something, there is an essence that GIVES the extra fire dmg, so I went and crafted one that’s not only BETTER than the one I paid for, but cheaper by a whole 27ex, the essence was 2 exalts and the base I used with 25% crit dmg bonus was 1 ex, I’m really proud of myself for actually REALIZING my mistake and being able to “profit” off it by getting a better wep for 99% off