To buy (or sell) VOID tokens, you can use Alcor.exchange. Click here https://wax.alcor.exchange/trade/void-onessusonwax_wax-eosio.token and connect with your wallet. VOID can be exchanged for WAX (WAXP), so you will need to have WAXP in your wallet to trade for VOID. WAXP can be bought at Kucoin, Binance, and OKEx, or with a credit card directly through your WAX Cloud Wallet.
You can place orders like on a traditional exchange, or simply swap. Some find it cheaper to use spot trading vs. the swap feature since swapping comes with high slippage and will likely cost you significantly more WAX than setting up BUY limit trade orders.
With BUY limit trade orders you are placing an order saying you are buying X amount of VOID tokens at N price per token. You can see this in the attached image which shows the Price field where you enter the maximum price you are willing to pay per VOID. The circled number is used here, which is the price of VOID from the most recent sale.
After entering in the price you wish to pay per VOID you enter the quantity of VOID you want to buy in the Amount field. After you have the Price and Amount box filled then the Total field will update.
The box at the upper right of the image with red text is the current SELL orders - people wanting to SELL their VOID for the price listed. These are prices you will be guaranteed to be able to buy VOID at. However, if you are buying a large number of VOID you may not want to buy up all the SELL orders, as the price may escalate very quickly. If you have the time, it's worth setting a reasonable BUY limit trade order and waiting for someone to sell their VOID at your asking price.
Keep in mind that you will want to monitor your BUY trade limit order since market conditions may change. You can see in the lower right section of the image the current BUY limit orders. If your BUY limit order price falls too far behind the other BUY orders here, then it may never get filled. You will then need to increase your limit if you are in a hurry or you think the market it going to start trending up. If you think the market will come back down, then just continue to be patient.