i would strongly advise you go into a dancewear store and get fitted for pointe shoes. there is much more to pointe shoe sizing than just length.
that being said, this is the closest to $30 that i can find:
http://www.discountdance.com/frame_set.php3?mf=http://www.discountdance.com/dancewear/style_202.html?/catalog_discountdance/Winter2008/custom/Redirect.aspx?rfx_spread=6&rfx_gid=327704&rfx_pageid=5&rfx_catalog=1&rfx_passback=&rfx_base=http%3A//discountdance.richfx.com.edgesuite.net/catalog_discountdance/Winter2008/&rfx_catalog_base=http%3A//discountdance.richfx.com/catalog_discountdance/Winter2008/index.aspx%3F&rfx_omni=1&rfx_OmniPageName=p6-7&rfx_OmniCatalogName=Winter2008&rfx_OmniClientID=discountdance&rfx_page=6&RFX_PassBack=&rfx_catalogname=Winter2008&rfx_catalog=1&
i would suggest, based on your street shoe size, going with a 10 (they are japanese, and run slightly odd), and they come in narrow, medium, wide, and extra wide (X). if you can wear regular, medium width sneakers and dress shoes, go with the wide. if you need narrow shoes, go with the medium. if you need wide shoes, go extra wide
i really hope you have had proper training. if not you can really screw up your entire body. pointe is a very dangerous activity, especially if you dont have a professional shoe fitting and if you are training yourself at home...
good luck.