As another alternative, how about light/medium dumbbells;

1) Experience the motion of a dumbbell
2) Experience the motion of a barbell
3) Reasons for using dumbbells
4) Reason for using barbells
5) Conclusion

While sitting down/standing up, place your left arm (this works for your right arm too) directly in front of you, while placing your right arm on your pectoral. Bring your left arm forwards and backwards (to and away from your body), while experiencing your pectoral contraction with your right hand.

Now, repeat this movement, with the same hand and arm in the same place in the same planes of motion. But instead, when your left arm is near-fully extended, move your fist across your body. With this movement, you will notice a greater pectoral contraction resulting from an increase in muscle fibre recruitment.

Now, once you have surpassed the heaviest dumbbell weight in your gym and are achieving a repetition range of 20+ reps, there really is no reason why you should continue to carry on using dumbbells. This is why people move on to barbell chest press exercises, whereby the load amount will be significantly higher than those experienced through dumbbell movements. Additional, from the reduced range of motion in contrast to dumbbell movements, ones joints are cared for to a greater extent - this is why you may see some previously injured gym members opting for barbell exercises.

To conclude, i believe that dumbbell chest press exercises are far superior than barbell chest press movements, up until a certain point - whereby the weights used/needed surpass those supplied by your gym, or unless you have a shoulder/pectoral injury.