Just a quick list of before buying tips...
Have rewards cards!
Staples, Kmart/Sears, Roundy's, County Market, CVS, etc... Staples has many items rebated back with your card and they give you rewards for recycling ink cartridges ($2 each with a max of 10 recycled a month). I save them up until I have 9 or 10, since rewards are issued in $10 increments monthly. You also get a 10% rebate back on ink and paper purchases.
If you're smart and don't go crazy - store credit cards - Victoria's Secret and Kohl's. Victoria's Secret sends out lots of coupons and freebies to card holders. Kohl's sends out up to 30% off your total purchase coupons a bazillion times a year - PLUS you can get Kohl's cash back, which sometimes is valid over a 30% off coupon time as well!
Example - this week I got an email from Staples for a bonus $5 rebate reward. I also had an ad coupon for $5 off a $25 purchase. This was great because I'd just run out of ink! I had 9 cartridges to recycle, so will eventually get $18 for those. I purchased the ink ($14.99), trading card holders (for couponing! $3.99), a clearance dual ring zipper binder with strap and handle! (regular $24.99 for $4.50), 2 sets of binder divider pages (regularly $2.99 each on clearance for 50 cents each!), and 2 rolls of clearance clear contact paper (50 cents each) = $16.58 oop after tax. So, basically I bought the ink and got the rest free :) AND I earned about $19 in rebates (the purchased ink gets discounted from the coupons, so the rebate isn't off the regular price which is kind of a bummer - but still savings). They also had a special of buying a pack of16 Duracell batteries for $9.99 and get the full amount of $9.99 rebated back (I passed on that since we mainly use rechargeable batteries and already have 2 16 packs of regular at home). Of course, my husband said I should have gotten them - but that would mean I'd have to find $40 worth of stuff to buy next time with the rebates! As much as I like a deal, I am trying to not buy just for the sake of buying.