I have two. My oldest was only $10 and doesn't even have a brand name on it (I think it was a Barska). The newer is marked Moboto and was about $15. On Amazon (or ebay) they have many brands and many of those look alike. Probably just a couple of factories in China making them with dozens of brand names put on. http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=camera+pistol+grip The first and third ones on this page look like my Moboto. It does seem to be a bit sturdier than the older one, at least it will screw on tighter and doesn't work loose as easy.*

I also came up against the problem of using the Red Dot to find distant subjects and use my flash (sometimes with better beamer) for subjects far off in poor light. They sell hot shoe splitters that will hold the Red Dot and the flash (or remote trigger) at the same time. A bit awkward at times but with experience I made the rig work. see pic below http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=hotshoe+splitter&rh=i%3Aaps%2Ck%3Ahotshoe+splitter

The Red Dot sights (if you get that far) are available in many brands, styles and prices. The cheapest work fine on a camera since they don't need to stand up to the recoil of a gun. One of mine was $19 and the other $24 (it has red and green color reticle choices, the older one red only).
http://www.amazon.com/s/ref=nb_sb_ss_c_1_13?url=search-alias%3Daps&field-keywords=red+dot+sight&rh=i%3Aaps%2Ck%3Ared+dot+sight
Both mine are like the first ones on this page, different names on them.

Since the sights were made to mount on guns you need an adapter for a hot shoe. MT Shooter here on the UHH (Carter's Camera Cottage) sells a very good one for $29 or so. He also is the US Distributor for the Nest Gimbal Head** - I use a Nest head and tripod.

*They do make ones with plugs for shutter releases on the grip. http://www.amazon.com/Professional-Handheld-Pistol-Tripod-Control/dp/B00985TO96

** Any Nest Gimbal heads you find elsewhere are either re-sales or they bought them out of the country (gray market).

New member here.. Thanks for the add.... I work in a Camera store. Some aftermarket lenses are really quite good.. Some lenses made by them are actually superior products compared to their Brand-specific counterparts (IE: Sigma 50mm f1.4... Check the reviews on that one... Plus, I have rented that one... !spectacular!) Tamron is actually the largest lens manufacturer in the world, so they get to concentrate on just making lenses. They also make medical application lenses and lenses for some of the camera companies to sell as their own according to Tamron. That 100-400 by Tamron is a good choice (it's fairly light and easy to hand-hold and carry... not nearly as big and heavy as you might think) It has a tripod mount you can buy for it if you decide you need it. Both Sigma and Tamron also make a 150-600, but those are both significantly larger and heavier. I rented the Tamron and I was able to hand-hold it for the limited time I used it (an afternoon walking around some hills) but if you are going to use it long term, a tripod or monopod are DEFINITELY needed.

There are 2 reasons pros buy their lenses from the brands they use:

1.Color: If you buy off brand, then the color balance might change...if you buy the same brand you get to keep that (Canon /Nikon/whatever brand) color and make sure that it's the same from lens to lens along your whole setup.

2.Features: If you buy the brand specific lenses then all the features that you are used to are there and are guaranteed to work with that lens. (One example: the lens barrels on Tamron and Sigma twist the opposite direction than Canon lenses do)