When you find the highest price, put your cards in an envelope and ship them to the address listed on their website
While a mana value of 3 is a pretty steep ask in cEDH, any other Commander deck containing black is usually improved by playing Grim Tutor
I wouldnt like to be facing this down
Depending on what kind of things you want this guy to be able to tutor for you can include appropriate cards in your deck so as to gain life, fix colours, find lands, find ramp spells, get card advantage, get mass removal, pump your guys and so on
Some of the balance in Pauper and other low power Cubes revolves around wide battlefields of 1/1s squaring off against creatures with two or more toughness
You could also throw a few bigger cards into the mix, such as Bloom Hulk and Kioras Dambreaker , that represent both huge threats and synergize well with your gameplan