Flew from Clearwater/St. Pete FL to Huntington WV on 1 Nov 13 with a carry-on and an electronics/laptop bag and experienced no problems; especially since both bags met the dimensions and weight requirements as specified on the Allegiant website and also included in the ticketing information. On 15 Nov 13 my return trip from TRi-State Airport in Huntington WV, I had the same carry-on luggage minus some clothing and shoes that I mailed home. Upon reaching the departure gate I was told by the person taking the boarding passes that my carry-on was over-sized and would not fit in the overhead bin and my electronics/laptop bag would not fit under the seat. I explained these are the same two items that I traveled with on 1 Nov 13 and they did actually fit. My explanation fell on deaf ears and the security guard was called over. I had initially paid $20 for this bag as a carry-on and I was bullied into paying and additional $50 in order to make my return trip to FL. What was really disturbing was other passengers had carry-on luggage larger than mine and were allowed to board the flight without incident. The other passengers were Caucasian and I was one of two Black passengers.