What type of gigging are you looking to do?
from a boat? or wading.
I wouldnt recommend gigging from a yak, tho I would say it can be a good vehicle to get you to other places to wade and gig. There is not enough stability in a yak to be dealing with spears in the dark.
Depending of what type of gigging you are looking to do I can give you a few suggestions for cheap set ups.
as for gigs. I recommend the alumnium shaft/stainless steel head gigs that you can pick up at gander, academy, or strike zone. they are 50 or 60 bucks if i remember but will last FOREVER.
After further thought. I figured id add all the info anyways so that others with different situations can also read some of my ideas/ advice.
Now I dont claim to be a flounder gigging genius by any means. But I have spent many hours researching and thinking up different set ups for flounder gigging.
As for lights. there are two paths you can take on a boat, and one path wading (unless your crazy)
You can either run with a generator or battery system in a boat, and typically battery systems only for wading.
As for boat gigging I myself (along with my gigging buddy) prefer batteries. they are more quiet and it makes the night much for fun and enjoyable over listening to a generator run all night. generator setups tend to be more straight forward and to the point, the more power, the more lights, shazam your gigging. But this is not so budget friendly.
As college kids with not a lot of money we wanted to get into gigging as cheap as possible to see if we liked it and were sucessfull before dropping a bunch of money on it. we gig out of a 12 foot jon boat with a plywood platform on the front of the boat. Our original setup was powered by 2 12 volt deep cycle batteries that we have had laying around. We went to the local hardware store, picked up 4 of those clamp on lights with metal reflector bowls and attached 2 on the front of the boat and 2 on the side angled off the front corners of the boat. with the purchase of a couple 12v lightbulbs we were able to wire up a system of 4 lights that ran off 2 batteries (2 lights per battery) that would last ALL night. We did have an extra battery for backup. These lights were above water lights and to be honest we never had an issue with glare.
This is probably the cheapest way to try gigging from a boat. with little investment and still can produce plenty of light. I do recommend using a good bit of silicone to seal off the switches on the lights and any other place water can get in and just use your battery terminals as switches. these lights lasted us 2 years before we decided to upgrade our setup. Since then we have moved onto a much brighter LED setup. We now run a 4 foot LED bar off the front of the boat that is submersible. This thing is BRIGHT and lasts MUCH MUCH MUCH longer than our previous setup. However i have noticed with our water here that the LED lights do not penetrate the dirty water as well as our previous setup. There is a lot of information about LED vs. Halogen in the gigging world and a simple google search will get you all the reading you want on that subject.
As for wading. I myself purchased a few waterproof LED flashlights that can be mounted on the end of a pole. Incredibly bright, long lasting, and compact. and best of all LIGHTWEIGHT.
Here is a video using my wading light setup

These lights have been good to me when I have used them, tho most of my gigging is from a boat.
I have heard of people going to the autoparts store and buying automobile headlights and rigging those into submersible gigging lights. this can be used for a boat application as well as a wading application, however these need power, and batteries can get heavy for wading. one popular fix is using a large cooler with a big PVC type boat. you float your cooler behind you, and in the cooler you can store your battery as well as drinks and fish.
Sorry for the long read but I hope this atleast helps somebody!
Kameron