Anything with fiber in it that tastes half way decent?
Easy and quick:
Pot of sweet peas, blend them.
Add some water and a broth cube.
Bring it to the boil.
Add some thin sliced sage and couple of minutes later some parsley (You could grow herbs in pots come year, and season all your food relatively cheap and really good)
Eat this soup with some whole wheat bread and you'll have lots of fibres, with lots of fluids coming with the meal too, since it is soup.
To make the soup even more tasty, and rich, add a dollop of sour cream and stir it well. Not necessary, but possible.
This may be too mild for your tastebuds. But, there is nothing wrong with experimenting with spices and herbs. Cooking your own food can be done cheap, and tasty, if you dare to invest first in spices and herbs.
You could make yourself some bean dishes, with lots of peppers in it. Beans are high fibre. And spicing it up may make you love them. Beans are a cheap way of getting your proteins too. Especially when you combine it with a grain component in your meal.
Adding some crushed flax-seed to yoghurt or to cereal makes a difference.
Chew everything you eat well. Drink lots of water. Fibres without enough fluids will only block you more, yes, fibres do become counter-productive if you forget to drink enough.
Tomatoes are a classic to get your system going again btw, as are some rye based cakes.