If $20 is keeping you from a decent clock, I'd say hold out until you can get the extra $20. I'm not being flippant. There are lots of things you can buy where the cheaper option is fine. In my opinion, a good clock is worth the money because it will last longer. You pay more now, but you make up for it by having a clock you can play for years.
Cheap Chess Clock

Two options. 1) Excalibur Game Time II can be had for $30-$40 if you look around. 2) DGT North American can be had for $40-$50.
The latter is a much better clock. I wouldn't waste money on anything cheaper than #1, and #2 is likely the only clock you'll ever need.

There's a guy I play blitz with sometimes who has the DGT North American. This player is pretty abusive to his clock (why press the lever when you can pound it, I guess) but the clock takes the beating and keeps working flawlessly. If I ever felt the need for a second clock, I'd seriously consider it.
I completely agree with the idea of saving to get the better clock.
At $89.99 on eBay the DGT 3000 is the best current available clock for the money. Yeah that is more saving, but the larger and more informative display (it shows seconds at all times) makes it worth it.
If you need a clock faster and do not have that much, the DGT NA in the $40 - $50 range is the best choice. It has delay and works well.
Spending less and getting a cheaper brand as you mention would be a waste of money. Those clocks notoriously do not last long before not working right.
So, save your money up and buy the DGT 3000 as the best option or spend less and get the DGT NA with the smaller and slightly less complete display.
I own both and find the 3000 to be just that much better.
I've been wanting a new chess clock for a while now. Going around the tournament hall begging for an extra clock works, but it gets old after a while.
Anyway, I thought to myself, "I don't have much money, but I could totally spend like $20-$30 on a new clock. I deserve it!" I had my heart set on Saitek Competition Pro Digital Chess Clock but they want 50 bucks for it!! I found that Leap Professional chess clocks are in my price range, but I've never used Leap before, and I don't know if it's any good. do you have any suggestions?