you can just spend your money on gear. Meaning clothes and a gym membership if you dont have one. Try to find photographers that will do test shoots for free. Usually they do it to experiment , re-new their portfolio or even for fun. That will give you some alright pics or even great. Then send them by e-mail to agencies. If some reply, good. If not, try to figure out what you did wrong and do it again. As long as you REALLY believe you can do this! Then try walking in as well. When I first started, I got an answer from an agency that was almost telling me to f... off... and that I couldnt do it!
Very rude..got pissed off did more shoots and later got into very good agencies. So it takes a lot of work effort and even if you get in, you get to hear, at least for me, 85% negative answers from castings! In the beggining I was devastated and talked about it freaking out to my agent...she said ''are you crazy?! This is good! you're doing well'' :-) It is a very competitive job but it is fun and when you start earning money after all the work it feels good! Hope I helped!