Congratulations on your new position!
Do you have any equipment at all? The least expensive equipment is going to be functional training equipment rather than individual machines.
Andrew’s suggestions about stability balls, med balls, and resistance bands are all good suggestions. There are also BOSUs, jump ropes, gliding discs, and Bender Balls, LeBert equalizers, which are also reasonably priced.
Sebastian mentioned TRXs. Also consider looking into CrossCore, which has a pulley at the top instead of a fixed anchor. This enables you to stabilize against AND create rotation in the transverse plane. Also, you can clip off one or both handles to add attachments. My favorites are to take off one handle and attach a kettlebell at one end to convert it to a cable machine, and a bar by Stroops that I attach to both ends.
The suggestions for used equipment isn’t a bad idea depending on your budget. Play it Again Sports sells a lot of used equipment from free weight to full-on machines.
Also, stability balls and bands offer a lot of exercises for a cheap price. TRXs are also good, they are a little pricey but offer a whole gym’s worth of exercises.
have you looked at used equipment? If you google ‘used commercial fitness equipment’, you will get quite a list.
Unfortunately, you say that you need it fast. Else you could contact the clubs around you to see when they plan on upgrading and see whether you can take their old equipment.