Baby Shower Invitation

Hello:
My mom and I are hosting a baby shower for my sister. It will be at my mom`s home, 1800 miles from where my sister lives. We`re from a culture where, traditionally, you don`t buy things for a baby that is not yet born. However, we do have a party of sorts that is for family and friends to shower blessings on the mom-to-be. Since we live in America, where things are different than the homeland, we`ve all taken to the practical aspect of baby showers and having the nursery ready for the baby. That said, what would be the best way to word a request for small or cash gifts since many of those invited will want to bring something and my sister will not have time for the hassle of packing up huge baby gifts and shipping them cross-country. Thanks.