So $ 400 is very tight, even when choosing the minimum quality needed for enjoyable views and to keep using the scope in the future.
With the telescope, that budget is on the tight side and may need some stretching, as you need the telescope tube, 2 (or 3) eyepieces to view the images at different magnifications, (low (medium) and high), a star diagonal to save your neck and provide comfort while viewing high in the sky and lastly you will need a mount. So $ 400 is very tight, even when choosing the minimum quality needed for enjoyable views and to keep using the scope in the future.