After you successfully grow your first crop, visit the market and put it up for sale.
At this time, you can set the price as high as desired and the customer will buy it. 
As soon as your crop is sold, visit the shop. The two most important upgrades to buy 
first are the five box stacker and the water jug upgrade. 
Pay attention to the demand level of the crops. Adjust your pricing based on the demand 
levels at a certain time. Try the following prices for each demand level. 

Extremely low:  $2
Very low:       $3 to $4
Low:            $4 to $5
Below average:  $5
Average:        $6 to $7
Above average:  $8 to $9
High:           $10 to $11
Very high:      $12 to $13
Extremely high: $14 to $15