Price doesn't always indicate quality as some sellers may have additional costs, low turnover or just want a very high margin. You really need to look at the specification of the frame, actual aluminium used, butting, geometry and various other factors. Most aluminium frames are coming out of far east factories with a factory door price less than $20. If you think of a scale of 1 to 5 for aluminium frame pricing with 1 being the cheapest and 5 being the most expensive I tend to be a '2' guy which seems to offer the best value before diminishing returns. I think the trouble is you often get scale '2' aluminium frames that are also sold as '3' or even '4' occasionally in my opinion by some companies who are more about marketing and lifestyle than actual value.