Just search "hobby phone" at the top.

I wouldn't bother with one. Some girls, such as myself are totally fine with email only contact. You can also just use Google Voice.

You can also just keep doing what you're doing. As long as you've done your homework and you see women so rarely, I don't see the need for a change. You will be in far more trouble if someone finds your soare well-hidden cell phone than digging through your bill for a random phone call.

If you're Married or have a GF, you're going to get caught eventually. Drop Phone or not. I'm Single so I can see my Girl anytime I want. No Sneaking around or Worries about getting caught.

I'm single.  I like having a drop (or burner) phone as my hobby phone.  On the off chance she turns out to be BSC, I can just lose the SIM card, get a new one, and be free of the drama.  I had to do this once after a lady started down a road of setting me up to extort me.  I saw it coming a mile away.  Because she didn't know anything but my hobby phone number...she was cut off 100% when I destroyed the SIM.  You could do the same with Google voice...

I also like it because it offers a layer of insulation.  I never really carry the hobby phone.  I don't have to worry about friends or family seeing some odd text hit my cell or getting a call and addressing the "who was that?" type scenario while chatting with my mom, etc.  I only get that phone out to engage in hobby related business.  I still have to lie to the people in my regular life.  But, I feel having the hobby phone and segmenting hobby-life from real-life allows me to minimize the need.

In the end...do what works for you.  This works for me.

virgin mobile phone that cost about $20 and I spend about $20 every 3 months to top-up. Not because I need the additional minutes but to keep my account active. The phone as well as the hobby email are in a "stage name" with no real address since everything is purchased with cash so as not to leave a paper trail.

guys with a SO will not be caught unless they are sloppy.  However, a hobby phone & a hobby email is only the first layer.  I knew of one guy who reportedly got caught before he ever saw a girl...  wife had access to his mail & got the girl's reply!!  A hobby phone costs 20 +20 every 3 months for service.  So 100 for the first year. If you can afford to hobby, you can afford the phone.  Ask Tiger about using your personal phone.  
As has been said buy phone with cash & air time with cash.  Register to a fake address...  trac fone has default probably the company offices in Florida.  You do not need to link to an email.  

Off topic but another couple of tips...    
do not access adult sites it anyone might walk in on you.
Unless you own the company & have no one to answer to...  do not use company computers or connection to access adult sites.  (Guys have been fired from 6 figure jobs over this!)    
Never use another person as a cover for hobbying...  
This is a secret world...  tell no one...  you never know when an ex-friend or drunken buddy will blurt something out & get you screwed (wrong way).