Yes, I think one score is necessary, but a portfolio is an option available for just this sort of situation--where full testing would be a true hardship.
There is financial help available from DYS once you have been in the group for 6 months, I think it is. So the testing might be something of an investment in future help. My understanding is that the program rarely pays completely for anything, but that poverty is not necessary to get some help from them for things like school, camp, computers, books, etc.
We're homeschooling, and it has been very helpful to have the social connections--probably even more for me than for DS8! Being able to discuss our situation openly and completely, and to ask for ideas about resources without having someone say "your child is too young for that!" has been helpful.
If nothing else, I think of DYS as insurance for the future. Who knows what will be appropriate for DS8 in future years? Even if we homeschool all the way through, at some point I suspect I'll have to advocate to get him into college classes earlier than at 18yo, and having more than my say-so that he's HG+ might be useful for getting his needs met. He may want to attend a more traditional school when he hits puberty, and I would probably need some advocacy help then. Who knows?
Also, there are the online seminars for kids and parents with experts in an amazing variety of fields. That's a pretty neat benefit!
DYS membership has been worth it for us. Actually, even without DYS, the testing was very useful to us for homeschooling. In our case, it helped me to realize that DS8's speed issues were real and more than just his dawdling. It changed the way I approach teaching him and helped me to meet his needs in a way that I was not doing before testing. I'm also a lot calmer and more realistic about how long things should take him. That's made homeschooling so much more pleasant!
HTH!
