I prefer to DIY my brake fluid, because I know exactly what grade of brake fluid I am getting. Some chain I worked for used the cheapest DOT3 there was, and it would turn dark brown after one year. DOT4 was only used on cars that required it, and there was a significant price increase to the customer.
Typically: Cheap DOT3 flush $90
Some kind of DOT4 $120
So I use Valvoline DOT4 on non-abs systems, it says clean for at least 2 years, and costs $7-$8 per quart. On ABS brakes, I use Pentosin DOT4LV because the low viscosity is supposed to make the ABS cycle more quickly. I pay $15-$17 per liter, and it stays clean for at least 2 years.