You can get a Razor II 1-6x for less than $1k. I think they're an excellent option.
I have Bushnell 1-6.5x SMRS II optics on my 16 and 17. They were a good deal when I bought them on close out, but current prices I would get a Razor if shopping new. You might check the EE for the SMRS if you want something cheaper and are willing to go used. You might find one for around $600.