XBoxHDM + nDure is pretty much what you want for Softmoding. it uses the hotswap method. i did this quite a few times on several XBox's using a old Emachines PC to do it just in case
and as usual... there IS some risk of damage to the PC and/or XBox. but that said i did it many times on my old Emachines PC and it's still working. so take this for whatever it's worth.
basically the basic idea... is connecting the PC's IDE cable to the XBox1's hard drive and running stuff from that XBoxHDM boot cd (which boot from PC) and modifies the stuff on the XBox hard drive to get it to do all the fancy stuff. ... i mostly use my XBox1 as a video player as i have XBMC (XBox Media Center) as my primary dashboard on it since a high high percentage of my use of XBox 1 is for .avi (XviD) playback. but your stock XBox1 console will have about 4.5GB free on the E partition after it's softmoded. (also, depending on what drive you got in your XBox1, it's possible to squeeze out about 2GB more on a F partition. but i think you have to have a Seagate hard drive in your system in order to get that. but as far as XBox1 games, this is completely useless. but it could be nice for extra storage of emulators etc etc)
but basically the XBoxHDM and nDure stuff is 100percent free as long as you got a blank disc (i usually use CD-RW) and a CD/DVD Burner.
p.s. it's also a good idea to get a copy of the original XBox dashboard and put it onto the XBoxHDM boot CD before burning the disc.