I have three of them. Two with AR High Mounts, and one with the Hunter Low Mount. EXCELLENT Red Dot Scopes! The three I have, are all Green/Red Dot, so I can switch between the colors, depending on the background I'm shooting at.
For $149, you can't beat them for the price. I found some inexpensive batteries for them on EBAY, and always keep a few extra in each of my Rifle Cases. You shouldn't find it hard to locate one for $149. I think that's pretty much the going price for most Sellers.
Are you wanting to Co-Witness with your BUIS?
Best of Luck!