For espresso you will find a stepless grinder of value. A good brand new, inexpensive grinder would be the Cunill Tranquillo at $275:
http://sovranastore.com/esgrin.htmlYou could go for a Baratza, but you would need to get a higher priced model to be espresso grind capable and they would be substantially more than the Tranquillo.
You will find it extremely convenient to keep one grinder for drip, pour over and other methods of extraction and another for
espresso.
If that is too much you can keep your eyes peeled on a used commercial espresso grinder. They will not set you back too much unless you insist on getting a conical burr.
I hope this helps.