Saving in Other Expenses

I have been trying to save money so I can achieve my goals, a student´s and mom life is not easy. Now I have to make another decision in my budget because I haven´t made up my mind which glasses I should buy.
I mentioned in my last post about this topic that I lost my good sunglasses and now I need to buy a prescription glasses too. The Sun glasses you see in my picture are a pair my hubby bought me but they have plastic lens, which I can´t stand. I use them mostly in my hair and not like real glasses. Now I need to buy two pairs instead of one because I started to have a hard time reading in the computer, probably I need to change my lens.
Prescription eyeglasses are expensive in Portuguese shops, my last pair cost me around 200.00 Euros and they are in plastic because I´m allergic to metals. Sunglasses with glass lens cost the same and I´m talking about cheap labels. I have two choices, either I buy in shops using my credit card, which I don´t want to, or I try to buy cheap eyeglasses. Both options have advantages and disadvantages but I have to decide.
Now I´m tempted to buy one pair of glasses in Zennioptical online shop because they have low prices and a vast selection of all types of frames and lens. They were featured in many different places like Fox news, the radio and in Clark Howard show. Ok, so the only way I can find out is buying one pair of eyeglasses, like the ones in the picture, which are very similar to the ones I use, and check it out for myself.