One suggestion that has worked well for many past participants: ask family members and/or friends to give you the gift of the retreat as a birthday, anniversary, or holiday (pre-Pesach) gift.
Another idea that was done in the past: a retreat staff or friend in your neighborhood posts on the email/WhatsApp group in your community asking women to donate small sums towards giving a woman in great need of a break the opportunity of coming on the wellness retreat.