Edging a garden?

Edging a garden?

Hello all, I'm new to this community, and sort of new to gardening. :) My husband and I recently bought a house last August, and this spring will be the first time I've ever had my own vegetable garden. The current garden in the house is 56' x 20'. Last fall I dumped about 3 inches of compost on top of it and let it sit there through the winter. I'm hoping to plant lettuce, tomatoes, squash, and some herbs. Right now, the garden is just a big open space in the yard. Should I edge it with something? My parents set down cedar timbers to edge their garden, and while it looks nice, it was also pricey. I checked out landscaping rock and brick, but they are also expensive for such a large area that I want to edge. I just want something to distinguish the garden from the lawn, and also something to help enclose the soil and maybe raise the bed up a few inches (so it will be less prone to slug attacks). If anyone has any ideas/advice, I'd be glad to hear of it! I live in the Pacific NW (Seattle) if that's any help. Happy gardening!
my apartment!

my apartment!

flower pressing

flower pressing

Another angle of the mystery bug

Another angle of the mystery bug

From an earlier post

From an earlier post

I really need help : (

I really need help : (

Kitchen Help!

Kitchen Help!