Well, potatoes are not totally bad for you. Based on the glycemic index they are considered bad in terms of negatively affecting your blood sugar level and based on the South Beach Diet and Atkins potatoes are scorned because it's a carb. Really, you could add butter to the potato to make it more blood sugar friendly, meaning adding butter or cheese to the potato won't spike your level as much as if you would just eat the potato by itself. I wouldn't throw them away - I would use them up, but next time don't buy so many or at least eat them off and on.
BTW are you a student? If so, I can understand your predicament trying to study, work, workout, and eat right. There are cheaper sources of protein out there like eggs and tuna, you could make a protein shake concoction, and other ways to afford it. I have read countless articles in Muscle and Fitness and Musclemag about college students trying to eat right on a budget.
You actually need carbs to fuel your cardio workouts. What kind of carbs are you eating besides salads and potatoes? Some folks add whole grains, like oatmeal, brown rice, and quinoa, to their diet which is good for fiber, weight loss, and to regulate blood sugar levels.
It sure looks like you're getting way too many carbs. Yes, consider eating every 2 to 3 hours and you need to make especially sure you are getting enough protein and a little bit of fat. For me I try to eat a little bit of protein at each major meal and for each snack. I eat 3 main meals and 3 snacks during the course of the day. Then again it depends on your goals and what eating plan you have chosen. If you're going on WW that makes it easier to count points, but if you want a fitness physique that won't necessarily work for you.
I have been exercising for years. I am a member of various fitness and bodybuilding sites and frankly that site (oxygenmag) and others have a lot of gals that already know how to eat and train hard. Have you consulted with a nutritionist or at least researched good nutrition to reach your goals? Having a good foundation helps a whole lot.
Also, you need to be aware of the amount of calories you're eating. Are you keeping track?
www.fitday.com is a good resource.
Are you doing any strength workouts? It makes a big difference.
HTH and keep it up