What are these speakers that came with my home worth?

What model are the Velodyne subwoofers? Should be printed on the metal plate on the back of the unit such as Digital Drive or Digital Drive Plus.

Veladyne subs are pretty much out dated vs Svs,rel, or JL audio
the speaker system go on Audiogon blue book to get a idea 
which is pretty close roughly 40% of the retail if you are lucky 
for they are not in high demand or even made any more that I am aware of .
i sold audio for a number of  years  and just telling you a true perspective 
just look online at other speakers for sale .rarelydoes any used speaker command even 50% of new price and the older it is the goes down ,
as well as if it is no longer made  ,something to keep in mind when trying to sell,plus original packaging , or local pickup only shipping is very expensive today.

When new everything maybe around $15k 
for everything maybe $6 k on a good day .

I did a little checking these are at least 15 years old ,and no longer 
made, these have powered amplifiers . You will just have to see what the market will bear . The buyer most likely will have knowledge of this type of speaker already , and likes its unique trades . These are selling if you go on ebay ,
or Audio shark for a fraction of their new price. The velodyne subs 
depending how old they are ,the newer ones have a microphone and Bass room correction  .this is why I said ,go to Audiogon 
Blue book and look up the model to get a ball park figure, and condition ,have you hooked them up to make sure they work perfectly . If need be have them put on consignment. Since they came with the house get what you can and market is very small 
on these ,this is going from just what I looked. Up. Best of luck.

hifishark is also a good resource to see what like items are selling for (or have sold for - click the sold/expired tab).