i've never heard of someone owning one except for swat or military...i'm talking about a semi auto version that would be legal.  and if so, how much $ they run?

There is a company I believe called Special Weapons that makes a semi-auto MP-5.  I thnik the going price is $1500-$1800.  They advertise in Shotgun News all the time.  I think they also have a website, but I'm not sure what the address is.

Hi there....hope I can help....it's called the H&K SP89, only available in pre-ban.....in  
90%+ condition look at a minimum of $2000-$2500 dollar, I sure would like an MP5/PDW myself. Again, I hope amd am of assistance.

Isaac

i just saw the one on gunbroker.com...almost 3k.
a guy can still dream though.

sp89s are so damn expensive becouse of George bushs 89 import ban ! damn him

Look into Special Weapons first.  I've heard bad things.  [V]

Do NOT buy any such weapon built, riveted, epoxied, or bubble-gummed together by Special Weapons.
Take the time, save up, and find yourself an HK 94. Then pay your $200 for your tax stamp on your form 1, plus whatever a GOOD class 2 will charge you to turn it into a legal SBR. Now you have a semi-auto MP5 that will actually hold its value, if not increase. Also, keep your eyes peeled, as just this weapon occasionally shows up for sale on certain NFA ad boards.
Happy hunting,
havoc

Don't buy a Special Weapons clone, unless you like to piss $1500+ down the drain.

Preban SP89s start at around $3000.  It is a semi-auto version of the MP5K and is registered as a pistol, so no forward grip, etc.

HK94s are the closest thing to a MP5 in semi, with a 16" bbl and of course are preban.  Average price is around $3200-3500 with some morons trying to sell at $4000-4500.

If it is legal in your state, you can pay the $200 tax stamp and have it SBRed to 9" bbl, the smith work will cost around $300 for a simple bbl hack and refinish, however you could pay around $700+ for a more authentic rebarreling and flapper mag release, etc.

Also, for about $4000 additional, you can add a registered autosear, if it is legal in your state.

or buy a sp89 have a sot add the foward grip then transfer it to you for 5 bucks and have a semi mp5k clone