Purchase mini DV

Dear all,

I am a neophyte and understands little of photo.

I wanted to buy a digital camera them in order to try to me in the video, but they have said to me that they are of low quality and they last little minutes, and have advised to me mini DV. Therefore I would want to buy it but I do not know just which to choose.

I have however of the priorities:

All, mini DV and UW case must cost little.

It must be small, in how much I must mount it on my speargun.

I had thought next to JVC GR-DVP3, or Sony DCR-PC5 but is not more in commerce. If I succeed to find one of the two used, even with relative guard, it is worth the pain buying them?

Thanks to anyone want to answer to me and to help me in the choice.