We would also like to know what are really good cheap special effects software that we can use.
Their isnt an "oh, all you have to do is this" kind of answer to your question. What you asked requires planning, resources and imagination.
You need to fill us in on what you intend to make. Is it high tech like lost in space the movie, or low tech like lost in space the tv show? What are you going for?
What you can do if you have a little money and alot of imagination is buy crap from thrift stores, yard sales, grandmas attic, anywhere you can find cheap junk and alter it ,glue it,paint it and make something out of it. Use cardboard for walls and then paint some abstract looking parts and affix them to it. The hard work will pay off.
As far as software goes, the ones everybody would suggest (which are constanly mentioned here, where have you been?) are photoshop, after effects. After effects is necassary is you intend to do bluescreen. These arent cheap but they are if you get them by shady means.
Im sure someone here has better suggestions for cheap effects software. But if you use cheap the outlook will look it. Which is cool if your going for "lost in space the tv show" though.

Where is this guy? If he wants a dialog then he has to participate in the discussion.
And yes it occured to me that you have things to do other than be on the net but its not like you have to drive to get to your computer and then pay a fee. Its at your home where you live and spend most your time. It would only take 5 minutes to check the board.
Anyways if you needed help then why havent you said anything else other than your explanations? You wont get much out of us if all you give us are vague questions and gaps in between posts. (to reiterate, not being rude just pointing out facts.)
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