I always stick to a VALUE dollar amount. I use the registry as a reference for what the bride/groom/parents want.
For instance, my cousin just got married and for the bridal shower, I went in with five other people charging them $10 a piece (they wanted to spend more but I didn't want to go overboard). I was able to purchase a coffee maker that brewed the individual pods in the color the bride wanted and it turns out she is the only coffee drinker in the house so she really loved it! She didn't want to put it on the registry because she thought it was too expensive (I bought mine 90% off at Target...a super awesome find) I then bought some dinner plates with matching salad plates and soup bowls in stoneware at target 75% off and an electric griddle I got a walmart for about half the price of the one they registered for at bed bath and beyond. I also got a pampered chef 9x13 stone pan I found at a dealer sale for around $16 brand new...Everything I bought was originally around $35-$90 each and I didn't spend any more than $60 on all the stuff combined. If I know someone is getting married I start asking questions...what colors are your kitchen, bathroom, living room, and bedroom. It's a great idea to go in on a big gift with someone because it loosens your budget a bit.
As far as baby showers go...once I know someone is pregnant, I start shopping the clearance sales for receiving blankets in ivory, white, yellow, or green (neutral baby colors). I also look for pacifiers (only ones that are orthadontic with a silicone nipple). I then get coupons for baby wash, baby shampoo, wipes, diaper cream, lotions, etc... I wait for a sale and stock up dirt cheap. I buy a laundry basket and line it with the receiving blankets (leaving the packaging under the blankets in case they want to return them) I then stack the wipes in the bottom (at least for different types...new mommies like to try everything once) then I arrange all the bottles of beauty aids as well as some onesies, socks, hooded towels, and outfits that are bigger (if it's a summer baby I buy winter clothes and vice versa) I also get cheap diapers at CVS because I combine an extracare coupon with a manufacturers coupon. Just one jumbo pack in size 2 or 3 because EVERYONE buys size 1 and most of the diapers get returned. They usually have nice coupons for huggies. Again, this is a really nice gift to go in on with someone. I also purchase big ticket items if my budget allows it such as the killer k-mart deals a while back with the car seat (evenflo triumph lx for $25), highchair ($20 for a really nice wooden originally $100), jogger stroller for $18 (originally $90), and a bassinet for $20 (originally $125 a really nice wooden one). You bring one of those bad boys to any baby shower and people wonder how you afforded it all!

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