If she has a job and is a responsible keeper already then she may be ready for one but there are some things to be aware of.
Costs First Year: Caging -first year- 30-40gallon tank with a wooden top $20-40
Substrate - first year - organic dirt/natural sand mixture 75/25 mix - $30
Feeding - first year - dubia roach colony of appropriate size - $200-500
Lighting - first year - 2-3 (+2 backup) 50WT Flood Light Bulbs + heat lamps to put them in - $60-100
Time: - First Month - Hands OFF - leave the animal alone and do not take him out of the cage
Second-Third month - Hands in the tank 20-30 minutes a day...everyday... this will get him/her used to your scent and prescence
Fourth-Fifth month - Begin picking him up INSIDE the cage but do not take him out.
Six Months Onward - Begin moving him to the bathtub for swims (filled to the level of his shoulders) and be incredibly patient with him, you need to have a very intimate understanding of his vocalizations and movements. You have to know when its the right time to put him away because hes stressed or whether he is just puffing because you moved wrong. At this time you can begin messing with his tail and stroking his back while in the bathtub.
Costs Second Year: Caging - second year - 4' long 4' wide and 3' tall Wooden Cage which your going to need machinery to make. Its probably best you break out a tape measure and show her how large that is. $200-500
Substrate - second year - 200-300lbs of dirt/sand 75/25 mix - $50-150
Feeding - second year - dubia roaches and 1 egg a week - $300-500 to prop up your colony's numbers
Lighting - second year - 4-6 (+4 for backups) 50WT Flood Lights and light strip mounted to ceiling of cage - $100-150
Costs Third Year: Caging - third year - 8' long 4' wide 4' tall Wooden Cage $300-800
Substrate - third year - $50-150
Feeding - third year - dubia roaches and 1-2 eggs per week - $300-500 to prop up your colony's numbers
Lighting - third year x2 of the second year
This is not meant to persuade her not to get one, it is ultimately her choice but trust me it is a very large commitment. Savannah Monitors are incredibly rewarding to work with as are all monitors due to their higher level of intelligence. I would recommend going with a Red Ackie if I was her, you can keep a pair in a 4' 4' 4' wooden box as outlined above forever. They eat the same as a 1.5 year old savannah does and they stay small. I'm not going to lie, I very much enjoy my 3ft monitor who is three years old now but at times I do wish he was a bit smaller (mostly because now he can escape from the bathtub on his own during swims

).