In REAL LIFE, a beginning graphic designer makes at least USD$20/hr (L$5000/hr). I doubt you will find anyone willing to pay that in SL. They want you to create a graphic for them and then they pay you L$250. (USD$1.00)
If you are truly a Commercial Artist, you wouldn't work for $1/hr, unless you are inexperienced and not really a *Designer*.
To your customers... They get what they pay for.