Choose one:
Cheap
Realistic
They're mutually exclusive. You get a cheap what-ever-it-is, and it's QUITE unlikely it's going to be realistic. You get a realistic one, and it's even less likely to be cheap.
Quality animal sex toys (I think I just threw up in my mouth a bit from actually typing those words together that way) truly are a "you get what you pay for" concept. Pay a little, get "not much" realism. Pay a lot, get something that at least approaches being somewhat realistic.
In between the two extremes, you WILL have to decide how much "real" you want to pay for. The more real, the more you'll pay - that's truly just the way it is.
If you think you can do it better for less, then by all means, go for it, and post a link to your web store once you get it set up. Otherwise, you're gonna have to figure out whether you want a "dog cock" dildo that looks like a human dick for some small amount of money, or a dildo that looks like an actual dog dick (and maybe even knots like a real dog dick) for a whole bunch of money.