Roy,
My opinion.....
There are plenty of scopes out there that produce very good digiscoped images and that don't cost as much as the ones you mentioned. The question is what type of image quality are you shooting for? Many of the "second tier" scopes such as the Vortex Razor you mentioned can produce very satisfying images in my opinion. With the interest in digiscoping increasing in recent years the ability to utilize a wide variety of scopes with either brand specific adapters or aftermarket adapters has never been better.
Second tier scopes to consider (in addition to the Razor) would be the Meopta Meostar S2, Nikon Fieldscope (discontinued but still available), Opticron HR ED, Pentax PF ED series, Zen Ray Prime, etc....
I personally use a relatively inexpensive Opticron MM3 50 mm scope and, understanding its limitations, get some very acceptable images with just my Iphone.
Some examples from my Flickr page....
https://flic.kr/p/xm3pDJ
https://flic.kr/p/xGmTrs
https://flic.kr/p/wmVVMt
https://flic.kr/p/uUeE4N