Here is the link for Nienhuis Montessori equipment.
On the equipment categories --
Infant and Toddler Imbucare boxes: You can select one or two to start out. You will find the prices are a good incentive to look at DIY.
Toddler Simple Puzzles: The two sets shown -- Single Shape and Multiple Shapes Puzzles -- are great because the introduce shapes and varying sizes of the same shape. Knobs that are easy to handle are key because you are building refined hand movements and fine motor skills.
Toddler Infilare Exercises: The Three Discs on a Vertical Dowel are surprisingly affordable. Again, you can pick three different sets out of the equipment line up here and be fine.
Toddler Supinated Wrist Movement: Worth buying a few because these are hard to make, unless you are unusually gifted with DIY. The Interlocking Discs are super popular with kids.
Infant and Toddler Dressing Frames: These are perfect for Montessori DIY!
The Threading and Braiding Material is definitely a good Montessori DIY project.
The Infant Mirror has a handle, which is fabulous, so check out the pic before making your own.
Infant Bell: Very cool. Good price, too.
Geography Material: The sandpaper globes and simple maps are really great to have at home. Globes make enjoyable and educational bedroom decor for children of all ages!
Practical Life: Sorting tray. I really like this one! See the pic above. You can make your own!