There are many ways to obtain a robe and many different robe to obtain.
I know in Chinese Buddhism most practitioner would wear a Hai Qing which is a type of robe that even people that didn't take any vow would wear.
In Vietnamese Buddhism there is something similar to the Hai Qing that lay Buddhist would wear without having to take any vows. It is generally grey but there are some that are brown.
If you want to remain a lay buddhist, you can also take precepts. In Chinese Buddhism if you take the 5 Upasaka(?) precepts you can wear something similar to that of a monastic.
(those wearing the Hai Qing and then the brown sash are lay buddhist that took precepts)
In Japanese Buddhism, Lay Buddhist that took precepts can wear a Rakusu that they received from their teacher or made by themselves
(The Rakusu is what being worn infront of them, looks like a bag)
I believe a robe can actually help people practice. Just like Kyudo, a Japanese meditative art of archery. The Kyudoka will wear their uniform when practicing. This is very important because once they had on their uniform, they step into a different mind set, leaving behind the busy noisy mundane world and entering another of focus and serenity. Practitioner can feel the different. When you wear jeans or t-shirt trying to practice Kyudo, it is as you are still distracted by the mundane world and can be an obstacle to practicing concentration.
I believe this is the same with Buddhism and its practitioner. The robe is mainly symbolic and can be an inspiration for practicing and to put you into a different realm/mind set. I believe that is the purpose of the robe....not to use as showing the hierarchy in Buddhism.
So yes! Get yourself a robe or make one yourself.