Having decided upon a machine (If possible, a little larger than you first anticipate ) The budget needs to cover some extra items.
You will need some tooling with the machine, whatever you buy.
You will need a vice (Buy a good one. A flimsy vice will spoil accuracy, at least.) It needs to be an appropriate size for the machine. Tilting Vices can be useful, but are less rigid, and can be bought as and when the need arises.
A Clamping kit may eventually prove useful, depending on what you do.
You will need a proper chuck to hold cutters, NOT a drill chuck. My choice would be the ER system.
Depending on what you want to do, you might need more than one size. ER25 will cover upto 16 mm, so may be a good starting point.
You will need End Mills, probably Slot Drills of various sizes, possibly one or more Face Mills..
You will certainly need twist Drills and either Spotting or Centre drills.
You are likely, eventually to want to cut threads, so you will need Taps and Dies. Again, you may well end up with several sets covering different thread types (Metric, posibly BSW, BSF, or even BA )
If, in the future, you want to produce regularly spaced holes, curved surfaces, or cut gears, you will need a Dividing Head or Rotary Table, preferably with a Tailstock.
You will need measuring equipment.
A digital Calliper would be a starting point, plus, possibly a Plunger Clock, and Finger Clock, maybe with a Magnetic Base. Later, you may decide to buy individual Micrometers, maybe even a Bore Set.
A six inch steel rule will be useful, if only for rough setting up.
Things like a n Edge Finder, or a Wiggler, and a Centre finder, are low cost accessories which make life easier.
You don't need to buy everything at once.
Buy the basics first of all, and add extras, as you see the need arising.
HTH
Howard