"that this is the lowest price" - my short essay of the common app

This is the first vision of my short essay, please help me to revise this essay. Thanks a looooot!

"I am sorry that this is the lowest price" I said straight and regrettable to the client. That was my first experience as a saleswoman. I have long been thinking of having my own business. Since I did not have enough money to pursue my dream, I decided to start my career at my school, selling my old things at the campus every noon. Luckily, after the long negotiation with my landlord, I got his promise that I can just borrow the house, which means I can save at least 5000RMB each month! I know that start a business is not the hardest thing of being a shopkeeper, but keeping the shop make profit is. By now, my shop has been there for four month, and I am sure that I will keep this shop until the day I go to America for better education as my new dream.

Suspended for ignoring the thread title rules.

To first proofread this, we must check the grammar. I said "regrettably"
"I know that starting a business"
And then I don't understand what "but keeping the shop make profit is" means.
"Four months" should be plural!

tsunami
Oh~ thanks a lot, I have just revised these grammar problwms. But how was the subject of this eaasy?

Maybe the common is using this topic to ask you an activity that is important for us, not only in material (such as making money), but also in spirit...so I think maybe you can write more than just stating how much the shop had earned...

Just personal view~