As SteveB said, there is no glass in the macro extension tubes - your friend is probably thinking about tele-extension tubes. The Kenko tubes have an electric pass-through so your autofocus will still work along with body set aperture settings. Add a 50mm 1.8 MKII to the tubes, (~$80 brand new), and you really are good to go for less than $200 (US).
For tripods I thoroughly recommend Amvona - professional build quality that compares to Bogen-Manfrotto for a fraction of the price. I got the
AT-858BL by DynaTran complete with grip ballhead for less than the price of a bogen head. It used to be that they sold all their stuff at huge discounts on eBay but it looks as though they are going straight in with low prices on their site now. Avoid any of the cheapo aluminium tripods that you can find in the local department store - unless you want to wreck thousands of dollars of equipment for the sake of a few bucks. The tripod I mention is rather heavy for carrying around all day but provides excellent stability. If weight is a real issue to you take a look at their carbon fiber range.
What body you got btw? (Not that it affects any of the above, just a nosey bastard).