Cash with a receipt is the way to go if the transaction is in person. But anything else requires some level of trust or monitoring of accounts. Checks give out more information about you and your bank account than your normal debit/credit card transaction. I find credit card transactions a good balance. Its reversible if its fraudulent and gives as little info as possible

Mount all your equipment on the wall. http://www.flat-panel-mount.com/flat_panel_arm_mou nt/LCD_arm_390.htm#m=2,2,1,1*t=2,2,1,1