This topic has been discussed ad nauseum so if you want a better discussion search for it, but long story short, yes there are plenty of cheaper alternatives.
My How to Be A Doctor 101 teacher told us it didn't really matter if we bought a Welch-Allyn set for hundreds of dollars, or one of the cheaper brands for practicing. 99% of the time, the devices will be there on the wall for you to use-- and those models are probably what you should get good at using. You'll notice a difference in your ability to visualize features of the eye, or the ability to adjust the brightness of the light (even between various Welch Allyn models), but it's not that big of a deal. So for $150, you can get a set off Amazon, then upgrade later if you decide you need to when you actually have monies.
That said, I bought a Welch-Allyn set off of eBay recently. Saved $400 over what it lists for new, and it works great. The warranty is transferable, and if I want to sell it later, I'll be able to and get what I paid for it or more back... if I don't, it's high enough quality that I'll be able to use it forever and have it around the house or whatever.