Inexpensive ideas for a baby shower.

A few guests can get together and get a big laundry basket. Place in it a long clothes line with outfits, diapers, bibs, etc. pinned to it. It can also be used as a room decoration. It has a bit of everything and something to carry it in!
Baby Quilt - here is a great gift from those that love to sew and quilt. Find an alphabet quilt pattern. Each square has a letter of the alphabet on it and a picture of an object that started with that letter. It can have numbers too. Each guest can be given/sent a square before the shower and can embroider, quilt, or embellish it according to her own taste. If the quilt is meant to be a wall hanging, guests can also attach little items like rattles and toys. Be sure that everyone signs their own block in some way and have the blocks returned by a certain date in order to have it put together. This can also be used as a decoration at the shower.
Make a scrapbook album. Take blank scrapbook pages and have everyone write down their well wishes (without Mom knowing it) for the new baby. This can be done at or before the shower and can be given at the shower or to Mom while she is in the hospital. If given after the shower, it can include photos taken there.
Pass out sheets of heavy paper decorated with baby related stamps, stickers, or pictures several lines drawn on. Have the guests write their name on the paper and then write down some baby/parenting advice. Once everyone is finished, collect them, add a cover, punch holes in it, and tie it together with some ribbon. Then hand it to Mom to read aloud. This will be entertaining as well as touching and is a nice keepsake. There is tons of room for creativity on this one.
Have each guest bring an extra gift (small item recommended) for Daddy-to-be and the host of the shower will then place them in large gift bag to present to him at the close of the party (usually after the main gifts are opened). He opens this with Mommy-to-be at home or in presence of close family or friends.
Diaper Shower--- For a second (or more) baby, consider a diaper shower. Ask each guest to bring only a package of diapers as a gift. Some guests may bring other gifts also, but Mom will end up with a mountain of diapers, something she will really need! Items could also include anything associated with diapering such as wipes, ointment, powder, etc.
Casserole Shower--- For the mother who has everything already, how about a Casserole Shower? Have each guest bring a casserole or other ready-to-cook meal that can be frozen or stored until after the baby is born. Be sure to have the containers clearly labeled with contents and any cooking instructions. How helpful that will be when Mom and Baby come home!
Book Party--- Have each guest purchase and give a copy of their favorite childhood book.