Below are the available creations I have made into step-by-step instructions for others to recreate themselves.  Instructions are in easy-to-follow PDF format and include the list of required parts.  Most have XML files included for use to upload to Bricklink for parts sourcing.  I only use authentic Lego pieces in color/part combinations actually available.  Occasionally I will utilize a few custom Brickarms parts. 

The actual cost of the parts for each varies greatly depending on which vendor you get them from, how many vendors required for all the parts, location of the vendor, whether you want used vs new parts, expediency of shipping, etc.  Custom kits generally cost much more than available retail kits with similar piece counts. 

The creations take a great deal of time and effort to design and turn into instructions, and this is reflected in the price.   I value my time, as I'm sure you do yours - that's why I put the time into making sure the instructions are easy to follow, make sense, and make the build enjoyable for you.