I have to agree with everything DaveT said in this thread. Based on what I believe will happen with Tesla in the near future, the stock will be at $500 within the next 3-6 years. $120 sounds like a bargain today, and there is no way the stock will ever go down to $70 without some very (unlikely) horrible news. If Tesla reaches all of its targets by 2017, the stock will for sure be worth at least $500. How it gets there I don't know, but if it goes down to $70 by the end of the year then you have a 10 bagger on your hands in just 3 years time - not going to happen.
I completely agree with sleepyhead's projections. $500 within next 3-6 years.
Here's a brief summary of some numbers for 2018 (or 2019) assuming Gen III is a success and Tesla sells 500k cars/yr (90k Model S/X, 410k Gen III):
17.6 billion revenue from 410k Gen III cars at average price of $43,000 ($35k base plus options. Also need to weigh in performance models).
7.4 billion revenue from 90k Model S/X cars at average price of $82,000 (inc. options and performance models).
So, $25 billion in total revenue for 2018 (or 2019).
Let's say they have 16% gross margin and 8% net profit ($2 billion).
Since Gen III is still in its early stages, Tesla is still in high-growth stage. Let's give them a 50x P/E.
So, valuation is $100 billion (or stock price of $769 based off of projected 130m common shares).
The reason why people will pay a 50 P/E is because in another 5 years (2023-2024), Tesla will likely sell 3x the amount of Gen III vehicles with new factories in Europe and China.
1.5 million Gen III cars at average $40k per car = $60 billion
200k Model S/X at $75k per car = $15 billion
(Note, I'm not including future roadster, truck, etc which will add more revenue)
So, total $75 billion in revenue.
If they have 16% gross margin and 8% net profit, then $6b in net profit.
Let's give them a 25 P/E since the electric car market is still growing strong at that point (by 2028 Elon Musk is forecasting over half of all new cars sold will be electric).
So, that's a $150b market cap ($1154 stock price based off of 130m common shares) in 2023.
These actually might turn out to be conservative numbers.