Is around 800 dollars for 70 units of botox normal pricing?

That sounds pretty average, as Botox can vary in price from $11 to $15 per unit. If you like your results and your injector, then I suggest you stick with them.

Hi Sakura.  The cost per unit is very competitive for a physician injector, but the issue seems to be how many units are injected.  For the area between the eyes (glabella) and the forehead, we would not be using more than 35 units of Dysport (105 units of Dysport), which would run about $400.  So, the price seems a little high just because the number of units being used for those areas is very high.  It seems like you have both ends of the spectrum there.  Very cheep and ineffective, but quite costly and effective.  There is a middle ground that includes less product and still great results.

I think you pretty much answered your own question. You are doing the right thing by having your Botox injected by a surgeon. With surgeon injectors you can expect to pay at least $12-$15 per unit of Botox. Your results seem to be lasting an appropriate length of time. If you are happy with your results then you should stick with your surgeon. Your face is your livelihood, you don't want to sacrifice your results just too save a few bucks. 

The cost per unit you quoted is quite reasonable. However, for those areas, I normally inject a total of 25-35 units. The number of units you were given seems high in my opinion.

I do not think that $800 for 70 units of Botox is overpriced, however 70 units seems like more than could possibly be needed to treat the forehead, between the brows and for an eyebrow lift.  Some people do need more than others and if you are getting good results, I would probably just stick with what you've been doing.