Pedals are a good thing to buy used. They are very reliable. You will also make many buying decisions that you will change your mind one and sell them back.

Ibanez TS-9 Tube Screamers can be had used for $75 - $85 U.S.

Boss Blues Driver can be had used for $50 - $75 U.S.

ProCo Rat Pedals can be had used for $50 - $100

Boss Super Overdrive can be had used for $40 to $65

I would start by evaluating those four pedals. There are plenty of YouTube videos comparing them or stacking them together. As far as getting sounds that many famous guitar players got, in order...[br]Tube Screamer

ProCo Rat

Blues Driver

In my opinion, the DS-1 is buzzy/fizzy at high gain. A better choice, in my opinion is the Boss Super Overdrive SD-1. The SD-1 is a Tube Screamer clone. And you can get them cheaper.