I bought the e-trex and quickly found I had wasted my money. On water, or in flat terrain it will work to get you from point A to point B. But that is about it.
I recently upgraded to th Garmin Oregon 450t. It comes with maps pre-loaded and very detailed maps are also available at extra cost. Without the maps you have no idea what may be between point A and point B such as steep mountains, rivers, roads etc. that must be navigated around. I have also found it much easier to use. It locks on in seconds and picks up signals in thick forests. I am part of a volunteer search and rescue unit. It has proven to be a great investment. I'd hold out for a better unit and spend money once instead of twice like I did.
If you have a smart phone, Cabellas has a map APP. I think it is free.
If you have a smart phone this is a good idea, but not alone. You still want a real GPS. If you are in an area with no cell phone coverage they are useless. They are not very accuate either. When we compared GPS coordinates recently the phone aps were off by about 400' on average. That is close enough for many uses, but not for what we do.