2 ways to fix that cracked housing cheap:
1) Take teckjohn up on his offer of the free part (very generous of you, teckjohn)
2)Weld your old one back together using a regular soldering gun. You might not be able to get it totally airtight, but you'd be amazed how well you can solder plastic pieces back together. Just get the tip of the gun hot enough to melt the plastic and start moving it back and forth across the edges of the break until it melts itself back together. Try it.