I've smashed my phone screen in the past and was able to find an online tutorial on how to replace it myself. So I ordered the parts and replaced and the phone worked fine, It was actually pretty easy.
Note that if you go this route, different phones have varying degrees of difficulty. I've replaced screens on phones where the manufacturer used so much glue that half the time I ended up destroying the LCD while trying to separate it from the metal backing (not even the glass, just the backing!). Others, the unit opens right up and everything separates easily. Disassembly videos online will give you a general idea of how to take it apart, but often times they have previously taken it apart to make disassembly during the video go easier.
My current phone was combined from two other phones. I picked up a broken Sprint phone off ebay which had a smashed screen, and combined it with a Cricket phone (sticking the Sprint motherboard into it) of the same model that had a functional display. Both were cheap, since Cricket went out of business so the phones no longer worked. At the time, my phone was going for $300 (used, but in good condition) on ebay; I got the two broken phones for around $50 each. Much easier than trying to replace glass or the LCD.