Despite what others may tell you, there is absolutely NOTHING wrong with buying a second-hand card. You'll likely never find a new 750 ti thats worth the price and comes with a worthwhile warranty these days, so a used unit is in order here.
Don't get me wrong, the 750 ti is likely the best card in the maxwell lineup, but if you must have a new GPU, I'd go with an rx 550 here. It's an extremely cheap card and typically performs on par with the 750ti (a little bit lower) New, this card goes for about $85.
If performance matters to you, go for a 560. It performs better than the 750 ti and about as well as a 1050. It's typically cheaper than the 1050 and can be found for $99 new (at least its under 100!).
All of the cards mentioned in...