what would it cost me to own?
Not too much, one arm, one leg, and the shirt off your back.
Really, if you have to ask...then you can't afford it.
I've done the sums for a number of similar propositions, and even cross hired with guarenteed hours (good luck with that), you'll be lucky to break even.
And that's not even allowing for unexpected costs, eg. early prop replacement, defaulting debtors, new ADs, etc.
If however it's just for personal use, rather than an investment, then J430s advise is fairly prudent.