I will start the ball rolling and hopefully others will jump in.
If I were trying to do this cheaply and easily, I would look for one or two used SB600 flash units and trigger them using the pop up flash on your D700. That way you can take full advantage of the Nikon Creative Lighting System (CLS). I imagine you could probably find some locally for about $150 to $200 each.
One draw back of this approach could be that you might not be able to sight the flash units withing the field of view of the pop up flash. (See your D700 manual for details) You could overcome that problem by getting for a used SB800 unit and use that as the flash trigger. That way the flash head can be aimed to trigger your remote flashes. I suspect you would pay about $300 for a used one.
If your budget wont stretch that far, you could buy some older Nikon flashes that support SU 4 (optical triggering) mode, but you will be restricted to operating in manual mode. Optical triggering is also problematic in terms of being triggered by other light sources. I guess the extent of that problem would be determined by lighting in the venue. I don't think your SB 24 flash unit supports optical triggering, and buying an adaptor might not be cost effective. I also don't believe your SB400 unit is going to be of any help because it does not support CLS.