Planning my raised beds

I am in the middle of a 78 hour work week, it has been eight days since my last day off and I have to be back at work in 6 hours. Its weeks like this when sometimes I need to step back and do something fun like garden planning!

I've already decided that I'm going to use raised beds to garden when we get out to our property there are a few reasons for this:

1. The natural soil VERY, VERY sandy and not at all nutreint dense. 

2. I have a bad knee (ski injury) and crawling around all day hurts.

3. I HATE weeds. 

So in my perfect world where money is no object and I can have whatever I want I would have 6-8  waist high raised beds with a non-soil growing medium. I haven't done all of the math but the cost for the lumber alone would be $120 per bed and each bed would require 4.4 cubic yards of material to fill. For reference topsoil costs about $60 for five cubic yards and soilless growing medium is more expensive than topsoil. All told ONE raised bed for a cost of +$200 for a total garden cost of at least $1200 is not practical for my family. 

Obviously I need to bring the cost down, so how about 6-8 sixteen inch high raised beds with a raised bed mixture of 60% top soil, 30% compost and 10% potting soil? This cuts my lumber costs in half so $60 and each raised bed will require approximately 1.75 cubic yards of material to fill. This means I will need 1 cubic yard of top soil ($12 per bed), .5 cubic yards of compost and about 5 cubic feet of soilless growing medium (potting soil). Compost costs about $20 per cubic yard so $10 per bed and potting soil will run $14 per 2.5 cubic foot bag so $28 per bed. That brings our total cost to $110 per bed . Still not cheap but I want to get at least a decade of use out of these beds so I think its a reasonable place to spend money and with this plan I don't have to spend a few years fighting ALL THE WEEDS.

Can this project be done for less money? YES! My mom built her raised bed for cost of about $20 as she used soil out of the garden and only needed to purchase the lumber, my sister built her raised beds out of pallet wood and garden soil for a total cost of $0. Cool, right?