I'm not sure anyone has said you should dump her if she won't accept a £50 ring.
As for your second paragraph. The belief that spending a little extra to make her feel special is important is just crazy. Surely the unconditional love and compainship is more than enough to make her feel special.
"Here you go dear, I spent a little extra just so you know how special you are" What complete rubbish!
Obviously you are just tight fisted! It's just money at the end of the day!
I feel sorry for anyone you ever date if you always put money first!
My wife and I have been together since we were both 15, it'll be 13 years together on the 5th march, and we'd of been married 1 year on the 2nd May. We are still very much in love, but that doesn't stop me buying her gifts now and then, flowers for no reason, or spend a little extra on jewellery for her. It shows her, beyond words that I appreciate her and hold her above everything else. It makes her feel special!
If you have a partner, would you not feel a little more special if they did a little bit of overtime to buy you that extra nice watch/TV/PC part you've been wanting? Would you not feel that little bit more important to them after they've made that extra effort?
My wife would be just as happy with nothing, but, I have the money, why not spend it?